content/base/src/nsObjectLoadingContent.cpp
author Wes Kocher <wkocher@mozilla.com>
Thu, 20 Feb 2014 16:19:30 -0800
changeset 170141 128cbf1edc402482d096b0acc820549b0a7ebe68
parent 170136 23dfc36f99d43a293666dc73422e6722e165f18d
child 170900 b6a4f6e8ef8c7dc9a56a9502cd9a7aec669f8605
permissions -rw-r--r--
Backed out 7 changesets (bug 406541, bug 738396, bug 852315, bug 971273, bug 971279) for various java/plugin-related failures on a CLOSED TREE Backed out changeset 13cc8a7ee925 (bug 852315) Backed out changeset 23dfc36f99d4 (bug 852315) Backed out changeset fb56bd7c0feb (bug 406541) Backed out changeset b24d1437c6f3 (bug 738396) Backed out changeset 5028e1290b45 (bug 971279) Backed out changeset 34ecdab0cfc2 (bug 971279) Backed out changeset 95b4aa01923d (bug 971273)

/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
// vim:set et cin sw=2 sts=2:
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
/*
 * A base class implementing nsIObjectLoadingContent for use by
 * various content nodes that want to provide plugin/document/image
 * loading functionality (eg <embed>, <object>, <applet>, etc).
 */

// Interface headers
#include "imgLoader.h"
#include "nsEventDispatcher.h"
#include "nsIContent.h"
#include "nsIDocShell.h"
#include "nsIDocument.h"
#include "nsIDOMDataContainerEvent.h"
#include "nsIDOMDocument.h"
#include "nsIDOMHTMLObjectElement.h"
#include "nsIDOMHTMLAppletElement.h"
#include "nsIExternalProtocolHandler.h"
#include "nsEventStates.h"
#include "nsIObjectFrame.h"
#include "nsIPermissionManager.h"
#include "nsPluginHost.h"
#include "nsPluginInstanceOwner.h"
#include "nsJSNPRuntime.h"
#include "nsIPresShell.h"
#include "nsIScriptGlobalObject.h"
#include "nsScriptSecurityManager.h"
#include "nsIScriptSecurityManager.h"
#include "nsIStreamConverterService.h"
#include "nsIURILoader.h"
#include "nsIURL.h"
#include "nsIWebNavigation.h"
#include "nsIWebNavigationInfo.h"
#include "nsIScriptChannel.h"
#include "nsIBlocklistService.h"
#include "nsIAsyncVerifyRedirectCallback.h"
#include "nsIAppShell.h"

#include "nsError.h"

// Util headers
#include "prenv.h"
#include "prlog.h"

#include "nsAutoPtr.h"
#include "nsCURILoader.h"
#include "nsContentPolicyUtils.h"
#include "nsContentUtils.h"
#include "nsCxPusher.h"
#include "nsDocShellCID.h"
#include "nsGkAtoms.h"
#include "nsThreadUtils.h"
#include "nsNetUtil.h"
#include "nsMimeTypes.h"
#include "nsStyleUtil.h"
#include "nsUnicharUtils.h"
#include "mozilla/Preferences.h"
#include "nsSandboxFlags.h"

// Concrete classes
#include "nsFrameLoader.h"

#include "nsObjectLoadingContent.h"
#include "mozAutoDocUpdate.h"
#include "nsIContentSecurityPolicy.h"
#include "nsIChannelPolicy.h"
#include "nsChannelPolicy.h"
#include "mozilla/dom/Element.h"
#include "GeckoProfiler.h"
#include "nsObjectFrame.h"
#include "nsDOMClassInfo.h"
#include "nsWrapperCacheInlines.h"
#include "nsDOMJSUtils.h"
#include "nsDOMEvent.h"

#include "nsWidgetsCID.h"
#include "nsContentCID.h"
#include "mozilla/BasicEvents.h"
#include "mozilla/dom/BindingUtils.h"
#include "mozilla/Telemetry.h"

#ifdef XP_WIN
// Thanks so much, Microsoft! :(
#ifdef CreateEvent
#undef CreateEvent
#endif
#endif // XP_WIN

static NS_DEFINE_CID(kAppShellCID, NS_APPSHELL_CID);

using namespace mozilla;
using namespace mozilla::dom;

#ifdef PR_LOGGING
static PRLogModuleInfo*
GetObjectLog()
{
  static PRLogModuleInfo *sLog;
  if (!sLog)
    sLog = PR_NewLogModule("objlc");
  return sLog;
}
#endif

#define LOG(args) PR_LOG(GetObjectLog(), PR_LOG_DEBUG, args)
#define LOG_ENABLED() PR_LOG_TEST(GetObjectLog(), PR_LOG_DEBUG)

static bool
InActiveDocument(nsIContent *aContent)
{
  if (!aContent->IsInDoc()) {
    return false;
  }
  nsIDocument *doc = aContent->OwnerDoc();
  return (doc && doc->IsActive());
}

///
/// Runnables and helper classes
///

class nsAsyncInstantiateEvent : public nsRunnable {
public:
  nsAsyncInstantiateEvent(nsObjectLoadingContent *aContent)
  : mContent(aContent) {}

  ~nsAsyncInstantiateEvent() {}

  NS_IMETHOD Run();

private:
  nsCOMPtr<nsIObjectLoadingContent> mContent;
};

NS_IMETHODIMP
nsAsyncInstantiateEvent::Run()
{
  nsObjectLoadingContent *objLC =
    static_cast<nsObjectLoadingContent *>(mContent.get());

  // If objLC is no longer tracking this event, we've been canceled or
  // superseded
  if (objLC->mPendingInstantiateEvent != this) {
    return NS_OK;
  }
  objLC->mPendingInstantiateEvent = nullptr;

  return objLC->SyncStartPluginInstance();
}

// Checks to see if the content for a plugin instance should be unloaded
// (outside an active document) or stopped (in a document but unrendered). This
// is used to allow scripts to move a plugin around the document hierarchy
// without re-instantiating it.
class CheckPluginStopEvent : public nsRunnable {
public:
  CheckPluginStopEvent(nsObjectLoadingContent *aContent)
  : mContent(aContent) {}

  ~CheckPluginStopEvent() {}

  NS_IMETHOD Run();

private:
  nsCOMPtr<nsIObjectLoadingContent> mContent;
};

NS_IMETHODIMP
CheckPluginStopEvent::Run()
{
  nsObjectLoadingContent *objLC =
    static_cast<nsObjectLoadingContent *>(mContent.get());

  // If objLC is no longer tracking this event, we've been canceled or
  // superseded. We clear this before we finish - either by calling
  // UnloadObject/StopPluginInstance, or directly if we took no action.
  if (objLC->mPendingCheckPluginStopEvent != this) {
    return NS_OK;
  }

  nsCOMPtr<nsIContent> content =
    do_QueryInterface(static_cast<nsIImageLoadingContent *>(objLC));
  if (!InActiveDocument(content)) {
    // Unload the object entirely
    LOG(("OBJLC [%p]: Unloading plugin outside of document", this));
    objLC->UnloadObject();
    return NS_OK;
  }

  if (!content->GetPrimaryFrame()) {
    LOG(("OBJLC [%p]: CheckPluginStopEvent - No frame, flushing layout", this));
    nsIDocument* currentDoc = content->GetCurrentDoc();
    if (currentDoc) {
      currentDoc->FlushPendingNotifications(Flush_Layout);
      if (objLC->mPendingCheckPluginStopEvent != this) {
        LOG(("OBJLC [%p]: CheckPluginStopEvent - superseded in layout flush",
             this));
        return NS_OK;
      } else if (content->GetPrimaryFrame()) {
        LOG(("OBJLC [%p]: CheckPluginStopEvent - frame gained in layout flush",
             this));
        objLC->mPendingCheckPluginStopEvent = nullptr;
        return NS_OK;
      }
    }
    // Still no frame, suspend plugin. HasNewFrame will restart us when we
    // become rendered again
    LOG(("OBJLC [%p]: Stopping plugin that lost frame", this));
    // Okay to leave loaded as a plugin, but stop the unrendered instance
    objLC->StopPluginInstance();
  }

  objLC->mPendingCheckPluginStopEvent = nullptr;
  return NS_OK;
}

/**
 * Helper task for firing simple events
 */
class nsSimplePluginEvent : public nsRunnable {
public:
  nsSimplePluginEvent(nsIContent* aTarget, const nsAString &aEvent)
    : mTarget(aTarget)
    , mDocument(aTarget->GetCurrentDoc())
    , mEvent(aEvent)
  {
    MOZ_ASSERT(aTarget && mDocument);
  }

  nsSimplePluginEvent(nsIDocument* aTarget, const nsAString& aEvent)
    : mTarget(aTarget)
    , mDocument(aTarget)
    , mEvent(aEvent)
  {
    MOZ_ASSERT(aTarget);
  }

  ~nsSimplePluginEvent() {}

  NS_IMETHOD Run();

private:
  nsCOMPtr<nsISupports> mTarget;
  nsCOMPtr<nsIDocument> mDocument;
  nsString mEvent;
};

NS_IMETHODIMP
nsSimplePluginEvent::Run()
{
  if (mDocument && mDocument->IsActive()) {
    LOG(("OBJLC [%p]: nsSimplePluginEvent firing event \"%s\"", mTarget.get(),
         NS_ConvertUTF16toUTF8(mEvent).get()));
    nsContentUtils::DispatchTrustedEvent(mDocument, mTarget,
                                         mEvent, true, true);
  }
  return NS_OK;
}

/**
 * A task for firing PluginCrashed DOM Events.
 */
class nsPluginCrashedEvent : public nsRunnable {
public:
  nsCOMPtr<nsIContent> mContent;
  nsString mPluginDumpID;
  nsString mBrowserDumpID;
  nsString mPluginName;
  nsString mPluginFilename;
  bool mSubmittedCrashReport;

  nsPluginCrashedEvent(nsIContent* aContent,
                       const nsAString& aPluginDumpID,
                       const nsAString& aBrowserDumpID,
                       const nsAString& aPluginName,
                       const nsAString& aPluginFilename,
                       bool submittedCrashReport)
    : mContent(aContent),
      mPluginDumpID(aPluginDumpID),
      mBrowserDumpID(aBrowserDumpID),
      mPluginName(aPluginName),
      mPluginFilename(aPluginFilename),
      mSubmittedCrashReport(submittedCrashReport)
  {}

  ~nsPluginCrashedEvent() {}

  NS_IMETHOD Run();
};

NS_IMETHODIMP
nsPluginCrashedEvent::Run()
{
  LOG(("OBJLC [%p]: Firing plugin crashed event\n",
       mContent.get()));

  nsCOMPtr<nsIDocument> doc = mContent->GetDocument();
  if (!doc) {
    NS_WARNING("Couldn't get document for PluginCrashed event!");
    return NS_OK;
  }

  ErrorResult rv;
  nsRefPtr<nsDOMEvent> event =
    doc->CreateEvent(NS_LITERAL_STRING("datacontainerevents"), rv);
  nsCOMPtr<nsIDOMDataContainerEvent> containerEvent(do_QueryObject(event));
  if (!containerEvent) {
    NS_WARNING("Couldn't QI event for PluginCrashed event!");
    return NS_OK;
  }

  event->InitEvent(NS_LITERAL_STRING("PluginCrashed"), true, true);
  event->SetTrusted(true);
  event->GetInternalNSEvent()->mFlags.mOnlyChromeDispatch = true;

  nsCOMPtr<nsIWritableVariant> variant;

  // add a "pluginDumpID" property to this event
  variant = do_CreateInstance("@mozilla.org/variant;1");
  if (!variant) {
    NS_WARNING("Couldn't create pluginDumpID variant for PluginCrashed event!");
    return NS_OK;
  }
  variant->SetAsAString(mPluginDumpID);
  containerEvent->SetData(NS_LITERAL_STRING("pluginDumpID"), variant);

  // add a "browserDumpID" property to this event
  variant = do_CreateInstance("@mozilla.org/variant;1");
  if (!variant) {
    NS_WARNING("Couldn't create browserDumpID variant for PluginCrashed event!");
    return NS_OK;
  }
  variant->SetAsAString(mBrowserDumpID);
  containerEvent->SetData(NS_LITERAL_STRING("browserDumpID"), variant);

  // add a "pluginName" property to this event
  variant = do_CreateInstance("@mozilla.org/variant;1");
  if (!variant) {
    NS_WARNING("Couldn't create pluginName variant for PluginCrashed event!");
    return NS_OK;
  }
  variant->SetAsAString(mPluginName);
  containerEvent->SetData(NS_LITERAL_STRING("pluginName"), variant);

  // add a "pluginFilename" property to this event
  variant = do_CreateInstance("@mozilla.org/variant;1");
  if (!variant) {
    NS_WARNING("Couldn't create pluginFilename variant for PluginCrashed event!");
    return NS_OK;
  }
  variant->SetAsAString(mPluginFilename);
  containerEvent->SetData(NS_LITERAL_STRING("pluginFilename"), variant);

  // add a "submittedCrashReport" property to this event
  variant = do_CreateInstance("@mozilla.org/variant;1");
  if (!variant) {
    NS_WARNING("Couldn't create crashSubmit variant for PluginCrashed event!");
    return NS_OK;
  }
  variant->SetAsBool(mSubmittedCrashReport);
  containerEvent->SetData(NS_LITERAL_STRING("submittedCrashReport"), variant);

  nsEventDispatcher::DispatchDOMEvent(mContent, nullptr, event, nullptr, nullptr);
  return NS_OK;
}

class nsStopPluginRunnable : public nsRunnable, public nsITimerCallback
{
public:
  NS_DECL_ISUPPORTS_INHERITED

  nsStopPluginRunnable(nsPluginInstanceOwner* aInstanceOwner,
                       nsObjectLoadingContent* aContent)
    : mInstanceOwner(aInstanceOwner)
    , mContent(aContent)
  {
    NS_ASSERTION(aInstanceOwner, "need an owner");
    NS_ASSERTION(aContent, "need a nsObjectLoadingContent");
  }

  // nsRunnable
  NS_IMETHOD Run();

  // nsITimerCallback
  NS_IMETHOD Notify(nsITimer *timer);

private:
  nsCOMPtr<nsITimer> mTimer;
  nsRefPtr<nsPluginInstanceOwner> mInstanceOwner;
  nsCOMPtr<nsIObjectLoadingContent> mContent;
};

NS_IMPL_ISUPPORTS_INHERITED1(nsStopPluginRunnable, nsRunnable, nsITimerCallback)

NS_IMETHODIMP
nsStopPluginRunnable::Notify(nsITimer *aTimer)
{
  return Run();
}

NS_IMETHODIMP
nsStopPluginRunnable::Run()
{
  // InitWithCallback calls Release before AddRef so we need to hold a
  // strong ref on 'this' since we fall through to this scope if it fails.
  nsCOMPtr<nsITimerCallback> kungFuDeathGrip = this;
  nsCOMPtr<nsIAppShell> appShell = do_GetService(kAppShellCID);
  if (appShell) {
    uint32_t currentLevel = 0;
    appShell->GetEventloopNestingLevel(&currentLevel);
    if (currentLevel > mInstanceOwner->GetLastEventloopNestingLevel()) {
      if (!mTimer)
        mTimer = do_CreateInstance("@mozilla.org/timer;1");
      if (mTimer) {
        // Fire 100ms timer to try to tear down this plugin as quickly as
        // possible once the nesting level comes back down.
        nsresult rv = mTimer->InitWithCallback(this, 100,
                                               nsITimer::TYPE_ONE_SHOT);
        if (NS_SUCCEEDED(rv)) {
          return rv;
        }
      }
      NS_ERROR("Failed to setup a timer to stop the plugin later (at a safe "
               "time). Stopping the plugin now, this might crash.");
    }
  }

  mTimer = nullptr;

  static_cast<nsObjectLoadingContent*>(mContent.get())->
    DoStopPlugin(mInstanceOwner, false, true);

  return NS_OK;
}

// You can't take the address of bitfield members, so we have two separate
// classes for these :-/

// Sets a object's mInstantiating bit to false when destroyed
class AutoSetInstantiatingToFalse {
public:
  AutoSetInstantiatingToFalse(nsObjectLoadingContent *aContent)
    : mContent(aContent) {}
  ~AutoSetInstantiatingToFalse() { mContent->mInstantiating = false; }
private:
  nsObjectLoadingContent* mContent;
};

// Sets a object's mInstantiating bit to false when destroyed
class AutoSetLoadingToFalse {
public:
  AutoSetLoadingToFalse(nsObjectLoadingContent *aContent)
    : mContent(aContent) {}
  ~AutoSetLoadingToFalse() { mContent->mIsLoading = false; }
private:
  nsObjectLoadingContent* mContent;
};

///
/// Helper functions
///

static bool
IsSuccessfulRequest(nsIRequest* aRequest)
{
  nsresult status;
  nsresult rv = aRequest->GetStatus(&status);
  if (NS_FAILED(rv) || NS_FAILED(status)) {
    return false;
  }

  // This may still be an error page or somesuch
  nsCOMPtr<nsIHttpChannel> httpChan(do_QueryInterface(aRequest));
  if (httpChan) {
    bool success;
    rv = httpChan->GetRequestSucceeded(&success);
    if (NS_FAILED(rv) || !success) {
      return false;
    }
  }

  // Otherwise, the request is successful
  return true;
}

static bool
CanHandleURI(nsIURI* aURI)
{
  nsAutoCString scheme;
  if (NS_FAILED(aURI->GetScheme(scheme))) {
    return false;
  }

  nsIIOService* ios = nsContentUtils::GetIOService();
  if (!ios)
    return false;

  nsCOMPtr<nsIProtocolHandler> handler;
  ios->GetProtocolHandler(scheme.get(), getter_AddRefs(handler));
  if (!handler) {
    return false;
  }

  nsCOMPtr<nsIExternalProtocolHandler> extHandler =
    do_QueryInterface(handler);
  // We can handle this URI if its protocol handler is not the external one
  return extHandler == nullptr;
}

// Helper for tedious URI equality syntax when one or both arguments may be
// null and URIEquals(null, null) should be true
static bool inline
URIEquals(nsIURI *a, nsIURI *b)
{
  bool equal;
  return (!a && !b) || (a && b && NS_SUCCEEDED(a->Equals(b, &equal)) && equal);
}

static bool
IsSupportedImage(const nsCString& aMimeType)
{
  return imgLoader::SupportImageWithMimeType(aMimeType.get());
}

static void
GetExtensionFromURI(nsIURI* uri, nsCString& ext)
{
  nsCOMPtr<nsIURL> url(do_QueryInterface(uri));
  if (url) {
    url->GetFileExtension(ext);
  } else {
    nsCString spec;
    uri->GetSpec(spec);

    int32_t offset = spec.RFindChar('.');
    if (offset != kNotFound) {
      ext = Substring(spec, offset + 1, spec.Length());
    }
  }
}

/**
 * Checks whether a plugin exists and is enabled for the extension
 * in the given URI. The MIME type is returned in the mimeType out parameter.
 */
bool
IsPluginEnabledByExtension(nsIURI* uri, nsCString& mimeType)
{
  nsAutoCString ext;
  GetExtensionFromURI(uri, ext);

  if (ext.IsEmpty()) {
    return false;
  }

  nsRefPtr<nsPluginHost> pluginHost = nsPluginHost::GetInst();

  if (!pluginHost) {
    NS_NOTREACHED("No pluginhost");
    return false;
  }

  const char* typeFromExt;
  nsresult rv = pluginHost->IsPluginEnabledForExtension(ext.get(), typeFromExt);
  if (NS_SUCCEEDED(rv)) {
    mimeType = typeFromExt;
    return true;
  }
  return false;
}

bool
PluginExistsForType(const char* aMIMEType)
{
  nsRefPtr<nsPluginHost> pluginHost = nsPluginHost::GetInst();

  if (!pluginHost) {
    NS_NOTREACHED("No pluginhost");
    return false;
  }

  return pluginHost->PluginExistsForType(aMIMEType);
}

///
/// Member Functions
///

// Helper to queue a CheckPluginStopEvent for a OBJLC object
void
nsObjectLoadingContent::QueueCheckPluginStopEvent()
{
  nsCOMPtr<nsIRunnable> event = new CheckPluginStopEvent(this);
  mPendingCheckPluginStopEvent = event;

  nsCOMPtr<nsIAppShell> appShell = do_GetService(kAppShellCID);
  if (appShell) {
    appShell->RunInStableState(event);
  }
}

// Tedious syntax to create a plugin stream listener with checks and put it in
// mFinalListener
bool
nsObjectLoadingContent::MakePluginListener()
{
  if (!mInstanceOwner) {
    NS_NOTREACHED("expecting a spawned plugin");
    return false;
  }
  nsRefPtr<nsPluginHost> pluginHost = nsPluginHost::GetInst();
  if (!pluginHost) {
    NS_NOTREACHED("No pluginHost");
    return false;
  }
  NS_ASSERTION(!mFinalListener, "overwriting a final listener");
  nsresult rv;
  nsRefPtr<nsNPAPIPluginInstance> inst;
  nsCOMPtr<nsIStreamListener> finalListener;
  rv = mInstanceOwner->GetInstance(getter_AddRefs(inst));
  NS_ENSURE_SUCCESS(rv, false);
  rv = pluginHost->NewPluginStreamListener(mURI, inst,
                                           getter_AddRefs(finalListener));
  NS_ENSURE_SUCCESS(rv, false);
  mFinalListener = finalListener;
  return true;
}


bool
nsObjectLoadingContent::IsSupportedDocument(const nsCString& aMimeType)
{
  nsCOMPtr<nsIContent> thisContent =
    do_QueryInterface(static_cast<nsIImageLoadingContent*>(this));
  NS_ASSERTION(thisContent, "must be a content");

  nsCOMPtr<nsIWebNavigationInfo> info(
    do_GetService(NS_WEBNAVIGATION_INFO_CONTRACTID));
  if (!info) {
    return false;
  }

  nsCOMPtr<nsIWebNavigation> webNav;
  nsIDocument* currentDoc = thisContent->GetCurrentDoc();
  if (currentDoc) {
    webNav = do_GetInterface(currentDoc->GetWindow());
  }

  uint32_t supported;
  nsresult rv = info->IsTypeSupported(aMimeType, webNav, &supported);

  if (NS_FAILED(rv)) {
    return false;
  }

  if (supported != nsIWebNavigationInfo::UNSUPPORTED) {
    // Don't want to support plugins as documents
    return supported != nsIWebNavigationInfo::PLUGIN;
  }

  // Try a stream converter
  // NOTE: We treat any type we can convert from as a supported type. If a
  // type is not actually supported, the URI loader will detect that and
  // return an error, and we'll fallback.
  nsCOMPtr<nsIStreamConverterService> convServ =
    do_GetService("@mozilla.org/streamConverters;1");
  bool canConvert = false;
  if (convServ) {
    rv = convServ->CanConvert(aMimeType.get(), "*/*", &canConvert);
  }
  return NS_SUCCEEDED(rv) && canConvert;
}

nsresult
nsObjectLoadingContent::BindToTree(nsIDocument* aDocument,
                                   nsIContent* aParent,
                                   nsIContent* aBindingParent,
                                   bool aCompileEventHandlers)
{
  nsImageLoadingContent::BindToTree(aDocument, aParent, aBindingParent,
                                    aCompileEventHandlers);

  if (aDocument) {
    return aDocument->AddPlugin(this);
  }
  return NS_OK;
}

void
nsObjectLoadingContent::UnbindFromTree(bool aDeep, bool aNullParent)
{
  nsImageLoadingContent::UnbindFromTree(aDeep, aNullParent);

  nsCOMPtr<nsIContent> thisContent =
    do_QueryInterface(static_cast<nsIObjectLoadingContent*>(this));
  MOZ_ASSERT(thisContent);
  nsIDocument* ownerDoc = thisContent->OwnerDoc();
  ownerDoc->RemovePlugin(this);

  if (mType == eType_Plugin && mInstanceOwner) {
    // we'll let the plugin continue to run at least until we get back to
    // the event loop. If we get back to the event loop and the node
    // has still not been added back to the document then we tear down the
    // plugin
    QueueCheckPluginStopEvent();
  } else if (mType != eType_Image) {
    // nsImageLoadingContent handles the image case.
    // Reset state and clear pending events
    /// XXX(johns): The implementation for GenericFrame notes that ideally we
    ///             would keep the docshell around, but trash the frameloader
    UnloadObject();
  }
  nsIDocument* doc = thisContent->GetCurrentDoc();
  if (doc && doc->IsActive()) {
    nsCOMPtr<nsIRunnable> ev = new nsSimplePluginEvent(doc,
                                                       NS_LITERAL_STRING("PluginRemoved"));
    NS_DispatchToCurrentThread(ev);
  }
}

nsObjectLoadingContent::nsObjectLoadingContent()
  : mType(eType_Loading)
  , mFallbackType(eFallbackAlternate)
  , mChannelLoaded(false)
  , mInstantiating(false)
  , mNetworkCreated(true)
  , mActivated(false)
  , mPlayPreviewCanceled(false)
  , mIsStopping(false)
  , mIsLoading(false)
  , mScriptRequested(false) {}

nsObjectLoadingContent::~nsObjectLoadingContent()
{
  // Should have been unbound from the tree at this point, and
  // CheckPluginStopEvent keeps us alive
  if (mFrameLoader) {
    NS_NOTREACHED("Should not be tearing down frame loaders at this point");
    mFrameLoader->Destroy();
  }
  if (mInstanceOwner) {
    // This is especially bad as delayed stop will try to hold on to this
    // object...
    NS_NOTREACHED("Should not be tearing down a plugin at this point!");
    StopPluginInstance();
  }
  DestroyImageLoadingContent();
}

nsresult
nsObjectLoadingContent::InstantiatePluginInstance(bool aIsLoading)
{
  if (mInstanceOwner || mType != eType_Plugin || (mIsLoading != aIsLoading) ||
      mInstantiating) {
    // If we hit this assertion it's probably because LoadObject re-entered :(
    //
    // XXX(johns): This hackiness will go away in bug 767635
    NS_ASSERTION(mIsLoading || !aIsLoading,
                 "aIsLoading should only be true inside LoadObject");
    return NS_OK;
  }

  mInstantiating = true;
  AutoSetInstantiatingToFalse autoInstantiating(this);

  nsCOMPtr<nsIContent> thisContent =
    do_QueryInterface(static_cast<nsIImageLoadingContent *>(this));

  nsIDocument* doc = thisContent->GetCurrentDoc();
  if (!doc || !InActiveDocument(thisContent)) {
    NS_ERROR("Shouldn't be calling "
             "InstantiatePluginInstance without an active document");
    return NS_ERROR_FAILURE;
  }

  // Instantiating an instance can result in script execution, which
  // can destroy this DOM object. Don't allow that for the scope
  // of this method.
  nsCOMPtr<nsIObjectLoadingContent> kungFuDeathGrip = this;

  // Flush layout so that the frame is created if possible and the plugin is
  // initialized with the latest information.
  doc->FlushPendingNotifications(Flush_Layout);
  // Flushing layout may have re-entered and loaded something underneath us
  NS_ENSURE_TRUE(mInstantiating, NS_OK);

  if (!thisContent->GetPrimaryFrame()) {
    LOG(("OBJLC [%p]: Not instantiating plugin with no frame", this));
    return NS_OK;
  }

  nsresult rv = NS_ERROR_FAILURE;
  nsRefPtr<nsPluginHost> pluginHost = nsPluginHost::GetInst();

  if (!pluginHost) {
    NS_NOTREACHED("No pluginhost");
    return NS_ERROR_FAILURE;
  }

  // If you add early return(s), be sure to balance this call to
  // appShell->SuspendNative() with additional call(s) to
  // appShell->ReturnNative().
  nsCOMPtr<nsIAppShell> appShell = do_GetService(kAppShellCID);
  if (appShell) {
    appShell->SuspendNative();
  }

  nsRefPtr<nsPluginInstanceOwner> newOwner;
  rv = pluginHost->InstantiatePluginInstance(mContentType.get(),
                                             mURI.get(), this,
                                             getter_AddRefs(newOwner));

  // XXX(johns): We don't suspend native inside stopping plugins...
  if (appShell) {
    appShell->ResumeNative();
  }

  if (!mInstantiating || NS_FAILED(rv)) {
    LOG(("OBJLC [%p]: Plugin instantiation failed or re-entered, "
         "killing old instance", this));
    // XXX(johns): This needs to be de-duplicated with DoStopPlugin, but we
    //             don't want to touch the protochain or delayed stop.
    //             (Bug 767635)
    if (newOwner) {
      nsRefPtr<nsNPAPIPluginInstance> inst;
      newOwner->GetInstance(getter_AddRefs(inst));
      newOwner->SetFrame(nullptr);
      if (inst) {
        pluginHost->StopPluginInstance(inst);
      }
      newOwner->Destroy();
    }
    return NS_OK;
  }

  mInstanceOwner = newOwner;

  // Ensure the frame did not change during instantiation re-entry (common).
  // HasNewFrame would not have mInstanceOwner yet, so the new frame would be
  // dangling. (Bug 854082)
  nsIFrame* frame = thisContent->GetPrimaryFrame();
  if (frame && mInstanceOwner) {
    mInstanceOwner->SetFrame(static_cast<nsObjectFrame*>(frame));

    // Bug 870216 - Adobe Reader renders with incorrect dimensions until it gets
    // a second SetWindow call. This is otherwise redundant.
    mInstanceOwner->CallSetWindow();
  }

  // Set up scripting interfaces.
  NotifyContentObjectWrapper();

  nsRefPtr<nsNPAPIPluginInstance> pluginInstance;
  GetPluginInstance(getter_AddRefs(pluginInstance));
  if (pluginInstance) {
    nsCOMPtr<nsIPluginTag> pluginTag;
    pluginHost->GetPluginTagForInstance(pluginInstance,
                                        getter_AddRefs(pluginTag));

    nsCOMPtr<nsIBlocklistService> blocklist =
      do_GetService("@mozilla.org/extensions/blocklist;1");
    if (blocklist) {
      uint32_t blockState = nsIBlocklistService::STATE_NOT_BLOCKED;
      blocklist->GetPluginBlocklistState(pluginTag, EmptyString(),
                                         EmptyString(), &blockState);
      if (blockState == nsIBlocklistService::STATE_OUTDATED) {
        // Fire plugin outdated event if necessary
        LOG(("OBJLC [%p]: Dispatching plugin outdated event for content %p\n",
             this));
        nsCOMPtr<nsIRunnable> ev = new nsSimplePluginEvent(thisContent,
                                                     NS_LITERAL_STRING("PluginOutdated"));
        nsresult rv = NS_DispatchToCurrentThread(ev);
        if (NS_FAILED(rv)) {
          NS_WARNING("failed to dispatch nsSimplePluginEvent");
        }
      }
    }

    // If we have a URI but didn't open a channel yet (eAllowPluginSkipChannel)
    // or we did load with a channel but are re-instantiating, re-open the
    // channel. OpenChannel() performs security checks, and this plugin has
    // already passed content policy in LoadObject.
    if ((mURI && !mChannelLoaded) || (mChannelLoaded && !aIsLoading)) {
      NS_ASSERTION(!mChannel, "should not have an existing channel here");
      // We intentionally ignore errors here, leaving it up to the plugin to
      // deal with not having an initial stream.
      OpenChannel();
    }
  }

  nsCOMPtr<nsIRunnable> ev = new nsSimplePluginEvent(thisContent,
    NS_LITERAL_STRING("PluginInstantiated"));
  NS_DispatchToCurrentThread(ev);

  return NS_OK;
}

void
nsObjectLoadingContent::NotifyOwnerDocumentActivityChanged()
{

  // If we have a plugin we want to queue an event to stop it unless we are
  // moved into an active document before returning to the event loop.
  if (mInstanceOwner)
    QueueCheckPluginStopEvent();
}

// nsIRequestObserver
NS_IMETHODIMP
nsObjectLoadingContent::OnStartRequest(nsIRequest *aRequest,
                                       nsISupports *aContext)
{
  PROFILER_LABEL("nsObjectLoadingContent", "OnStartRequest");

  LOG(("OBJLC [%p]: Channel OnStartRequest", this));

  if (aRequest != mChannel || !aRequest) {
    // happens when a new load starts before the previous one got here
    return NS_BINDING_ABORTED;
  }

  // If we already switched to type plugin, this channel can just be passed to
  // the final listener.
  if (mType == eType_Plugin) {
    if (!mInstanceOwner) {
      // We drop mChannel when stopping plugins, so something is wrong
      NS_NOTREACHED("Opened a channel in plugin mode, but don't have a plugin");
      return NS_BINDING_ABORTED;
    }
    if (MakePluginListener()) {
      return mFinalListener->OnStartRequest(aRequest, nullptr);
    } else {
      NS_NOTREACHED("Failed to create PluginStreamListener, aborting channel");
      return NS_BINDING_ABORTED;
    }
  }

  // Otherwise we should be state loading, and call LoadObject with the channel
  if (mType != eType_Loading) {
    NS_NOTREACHED("Should be type loading at this point");
    return NS_BINDING_ABORTED;
  }
  NS_ASSERTION(!mChannelLoaded, "mChannelLoaded set already?");
  NS_ASSERTION(!mFinalListener, "mFinalListener exists already?");

  mChannelLoaded = true;

  nsCOMPtr<nsIChannel> chan(do_QueryInterface(aRequest));
  NS_ASSERTION(chan, "Why is our request not a channel?");

  nsCOMPtr<nsIURI> uri;

  if (IsSuccessfulRequest(aRequest)) {
    chan->GetURI(getter_AddRefs(uri));
  }

  if (!uri) {
    LOG(("OBJLC [%p]: OnStartRequest: Request failed\n", this));
    // If the request fails, we still call LoadObject() to handle fallback
    // content and notifying of failure. (mChannelLoaded && !mChannel) indicates
    // the bad state.
    mChannel = nullptr;
    LoadObject(true, false);
    return NS_ERROR_FAILURE;
  }

  return LoadObject(true, false, aRequest);
}

NS_IMETHODIMP
nsObjectLoadingContent::OnStopRequest(nsIRequest *aRequest,
                                      nsISupports *aContext,
                                      nsresult aStatusCode)
{
  NS_ENSURE_TRUE(nsContentUtils::IsCallerChrome(), NS_ERROR_NOT_AVAILABLE);

  if (aRequest != mChannel) {
    return NS_BINDING_ABORTED;
  }

  mChannel = nullptr;

  if (mFinalListener) {
    // This may re-enter in the case of plugin listeners
    nsCOMPtr<nsIStreamListener> listenerGrip(mFinalListener);
    mFinalListener = nullptr;
    listenerGrip->OnStopRequest(aRequest, aContext, aStatusCode);
  }

  // Return value doesn't matter
  return NS_OK;
}


// nsIStreamListener
NS_IMETHODIMP
nsObjectLoadingContent::OnDataAvailable(nsIRequest *aRequest,
                                        nsISupports *aContext,
                                        nsIInputStream *aInputStream,
                                        uint64_t aOffset, uint32_t aCount)
{
  NS_ENSURE_TRUE(nsContentUtils::IsCallerChrome(), NS_ERROR_NOT_AVAILABLE);

  if (aRequest != mChannel) {
    return NS_BINDING_ABORTED;
  }

  if (mFinalListener) {
    // This may re-enter in the case of plugin listeners
    nsCOMPtr<nsIStreamListener> listenerGrip(mFinalListener);
    return listenerGrip->OnDataAvailable(aRequest, aContext, aInputStream,
                                         aOffset, aCount);
  }

  // We shouldn't have a connected channel with no final listener
  NS_NOTREACHED("Got data for channel with no connected final listener");
  mChannel = nullptr;

  return NS_ERROR_UNEXPECTED;
}

// nsIFrameLoaderOwner
NS_IMETHODIMP
nsObjectLoadingContent::GetFrameLoader(nsIFrameLoader** aFrameLoader)
{
  NS_IF_ADDREF(*aFrameLoader = mFrameLoader);
  return NS_OK;
}

NS_IMETHODIMP_(already_AddRefed<nsFrameLoader>)
nsObjectLoadingContent::GetFrameLoader()
{
  nsRefPtr<nsFrameLoader> loader = mFrameLoader;
  return loader.forget();
}

NS_IMETHODIMP
nsObjectLoadingContent::SwapFrameLoaders(nsIFrameLoaderOwner* aOtherLoader)
{
  return NS_ERROR_NOT_IMPLEMENTED;
}

NS_IMETHODIMP
nsObjectLoadingContent::GetActualType(nsACString& aType)
{
  aType = mContentType;
  return NS_OK;
}

NS_IMETHODIMP
nsObjectLoadingContent::GetDisplayedType(uint32_t* aType)
{
  *aType = DisplayedType();
  return NS_OK;
}

NS_IMETHODIMP
nsObjectLoadingContent::HasNewFrame(nsIObjectFrame* aFrame)
{
  if (mType != eType_Plugin) {
    return NS_OK;
  }

  if (!aFrame) {
    // Lost our frame. If we aren't going to be getting a new frame, e.g. we've
    // become display:none, we'll want to stop the plugin. Queue a
    // CheckPluginStopEvent
    if (mInstanceOwner) {
      mInstanceOwner->SetFrame(nullptr);
      QueueCheckPluginStopEvent();
    }
    return NS_OK;
  }

  // Have a new frame

  if (!mInstanceOwner) {
    // We are successfully setup as type plugin, but have not spawned an
    // instance due to a lack of a frame.
    AsyncStartPluginInstance();
    return NS_OK;
  }

  // Otherwise, we're just changing frames
  // Set up relationship between instance owner and frame.
  nsObjectFrame *objFrame = static_cast<nsObjectFrame*>(aFrame);
  mInstanceOwner->SetFrame(objFrame);

  return NS_OK;
}

NS_IMETHODIMP
nsObjectLoadingContent::GetPluginInstance(nsNPAPIPluginInstance** aInstance)
{
  *aInstance = nullptr;

  if (!mInstanceOwner) {
    return NS_OK;
  }

  return mInstanceOwner->GetInstance(aInstance);
}

NS_IMETHODIMP
nsObjectLoadingContent::GetContentTypeForMIMEType(const nsACString& aMIMEType,
                                                  uint32_t* aType)
{
  *aType = GetTypeOfContent(PromiseFlatCString(aMIMEType));
  return NS_OK;
}

NS_IMETHODIMP
nsObjectLoadingContent::GetBaseURI(nsIURI **aResult)
{
  NS_IF_ADDREF(*aResult = mBaseURI);
  return NS_OK;
}

// nsIInterfaceRequestor
// We use a shim class to implement this so that JS consumers still
// see an interface requestor even though WebIDL bindings don't expose
// that stuff.
class ObjectInterfaceRequestorShim MOZ_FINAL : public nsIInterfaceRequestor,
                                               public nsIChannelEventSink,
                                               public nsIStreamListener
{
public:
  NS_DECL_CYCLE_COLLECTING_ISUPPORTS
  NS_DECL_CYCLE_COLLECTION_CLASS_AMBIGUOUS(ObjectInterfaceRequestorShim,
                                           nsIInterfaceRequestor)
  NS_DECL_NSIINTERFACEREQUESTOR
  // nsRefPtr<nsObjectLoadingContent> fails due to ambiguous AddRef/Release,
  // hence the ugly static cast :(
  NS_FORWARD_NSICHANNELEVENTSINK(static_cast<nsObjectLoadingContent *>
                                 (mContent.get())->)
  NS_FORWARD_NSISTREAMLISTENER  (static_cast<nsObjectLoadingContent *>
                                 (mContent.get())->)
  NS_FORWARD_NSIREQUESTOBSERVER (static_cast<nsObjectLoadingContent *>
                                 (mContent.get())->)

  ObjectInterfaceRequestorShim(nsIObjectLoadingContent* aContent)
    : mContent(aContent)
  {}

protected:
  nsCOMPtr<nsIObjectLoadingContent> mContent;
};

NS_IMPL_CYCLE_COLLECTION_1(ObjectInterfaceRequestorShim, mContent)

NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(ObjectInterfaceRequestorShim)
  NS_INTERFACE_MAP_ENTRY(nsIInterfaceRequestor)
  NS_INTERFACE_MAP_ENTRY(nsIChannelEventSink)
  NS_INTERFACE_MAP_ENTRY(nsIStreamListener)
  NS_INTERFACE_MAP_ENTRY(nsIRequestObserver)
  NS_INTERFACE_MAP_ENTRY_AMBIGUOUS(nsISupports, nsIInterfaceRequestor)
NS_INTERFACE_MAP_END

NS_IMPL_CYCLE_COLLECTING_ADDREF(ObjectInterfaceRequestorShim)
NS_IMPL_CYCLE_COLLECTING_RELEASE(ObjectInterfaceRequestorShim)

NS_IMETHODIMP
ObjectInterfaceRequestorShim::GetInterface(const nsIID & aIID, void **aResult)
{
  if (aIID.Equals(NS_GET_IID(nsIChannelEventSink))) {
    nsIChannelEventSink* sink = this;
    *aResult = sink;
    NS_ADDREF(sink);
    return NS_OK;
  }
  return NS_NOINTERFACE;
}

// nsIChannelEventSink
NS_IMETHODIMP
nsObjectLoadingContent::AsyncOnChannelRedirect(nsIChannel *aOldChannel,
                                               nsIChannel *aNewChannel,
                                               uint32_t aFlags,
                                               nsIAsyncVerifyRedirectCallback *cb)
{
  // If we're already busy with a new load, or have no load at all,
  // cancel the redirect.
  if (!mChannel || aOldChannel != mChannel) {
    return NS_BINDING_ABORTED;
  }

  mChannel = aNewChannel;
  cb->OnRedirectVerifyCallback(NS_OK);
  return NS_OK;
}

// <public>
nsEventStates
nsObjectLoadingContent::ObjectState() const
{
  switch (mType) {
    case eType_Loading:
      return NS_EVENT_STATE_LOADING;
    case eType_Image:
      return ImageState();
    case eType_Plugin:
    case eType_Document:
      // These are OK. If documents start to load successfully, they display
      // something, and are thus not broken in this sense. The same goes for
      // plugins.
      return nsEventStates();
    case eType_Null:
      switch (mFallbackType) {
        case eFallbackSuppressed:
          return NS_EVENT_STATE_SUPPRESSED;
        case eFallbackUserDisabled:
          return NS_EVENT_STATE_USERDISABLED;
        case eFallbackClickToPlay:
          return NS_EVENT_STATE_TYPE_CLICK_TO_PLAY;
        case eFallbackPlayPreview:
          return NS_EVENT_STATE_TYPE_PLAY_PREVIEW;
        case eFallbackDisabled:
          return NS_EVENT_STATE_BROKEN | NS_EVENT_STATE_HANDLER_DISABLED;
        case eFallbackBlocklisted:
          return NS_EVENT_STATE_BROKEN | NS_EVENT_STATE_HANDLER_BLOCKED;
        case eFallbackCrashed:
          return NS_EVENT_STATE_BROKEN | NS_EVENT_STATE_HANDLER_CRASHED;
        case eFallbackUnsupported: {
          // Check to see if plugins are blocked on this platform.
          char* pluginsBlocked = PR_GetEnv("MOZ_PLUGINS_BLOCKED");
          if (pluginsBlocked && pluginsBlocked[0] == '1') {
            return NS_EVENT_STATE_BROKEN | NS_EVENT_STATE_TYPE_UNSUPPORTED_PLATFORM;
          } else {
            return NS_EVENT_STATE_BROKEN | NS_EVENT_STATE_TYPE_UNSUPPORTED;
          }
        }
        case eFallbackOutdated:
        case eFallbackAlternate:
          return NS_EVENT_STATE_BROKEN;
        case eFallbackVulnerableUpdatable:
          return NS_EVENT_STATE_VULNERABLE_UPDATABLE;
        case eFallbackVulnerableNoUpdate:
          return NS_EVENT_STATE_VULNERABLE_NO_UPDATE;
      }
  };
  NS_NOTREACHED("unknown type?");
  return NS_EVENT_STATE_LOADING;
}

// Returns false if mBaseURI is not acceptable for java applets.
bool
nsObjectLoadingContent::CheckJavaCodebase()
{
  nsCOMPtr<nsIContent> thisContent =
    do_QueryInterface(static_cast<nsIImageLoadingContent*>(this));
  nsCOMPtr<nsIScriptSecurityManager> secMan =
    nsContentUtils::GetSecurityManager();
  nsCOMPtr<nsINetUtil> netutil = do_GetNetUtil();
  NS_ASSERTION(thisContent && secMan && netutil, "expected interfaces");


  // Note that mBaseURI is this tag's requested base URI, not the codebase of
  // the document for security purposes
  nsresult rv = secMan->CheckLoadURIWithPrincipal(thisContent->NodePrincipal(),
                                                  mBaseURI, 0);
  if (NS_FAILED(rv)) {
    LOG(("OBJLC [%p]: Java codebase check failed", this));
    return false;
  }

  nsCOMPtr<nsIURI> principalBaseURI;
  rv = thisContent->NodePrincipal()->GetURI(getter_AddRefs(principalBaseURI));
  if (NS_FAILED(rv)) {
    NS_NOTREACHED("Failed to URI from node principal?");
    return false;
  }
  // We currently allow java's codebase to be non-same-origin, with
  // the exception of URIs that represent local files
  if (NS_URIIsLocalFile(mBaseURI) &&
      nsScriptSecurityManager::GetStrictFileOriginPolicy() &&
      !NS_RelaxStrictFileOriginPolicy(mBaseURI, principalBaseURI, true)) {
    LOG(("OBJLC [%p]: Java failed RelaxStrictFileOriginPolicy for file URI",
         this));
    return false;
  }

  return true;
}

bool
nsObjectLoadingContent::CheckLoadPolicy(int16_t *aContentPolicy)
{
  if (!aContentPolicy || !mURI) {
    NS_NOTREACHED("Doing it wrong");
    return false;
  }

  nsCOMPtr<nsIContent> thisContent =
    do_QueryInterface(static_cast<nsIImageLoadingContent*>(this));
  NS_ASSERTION(thisContent, "Must be an instance of content");

  nsIDocument* doc = thisContent->OwnerDoc();

  *aContentPolicy = nsIContentPolicy::ACCEPT;
  nsresult rv = NS_CheckContentLoadPolicy(nsIContentPolicy::TYPE_OBJECT,
                                          mURI,
                                          doc->NodePrincipal(),
                                          thisContent,
                                          mContentType,
                                          nullptr, //extra
                                          aContentPolicy,
                                          nsContentUtils::GetContentPolicy(),
                                          nsContentUtils::GetSecurityManager());
  NS_ENSURE_SUCCESS(rv, false);
  if (NS_CP_REJECTED(*aContentPolicy)) {
    nsAutoCString uri;
    nsAutoCString baseUri;
    mURI->GetSpec(uri);
    mURI->GetSpec(baseUri);
    LOG(("OBJLC [%p]: Content policy denied load of %s (base %s)",
         this, uri.get(), baseUri.get()));
    return false;
  }

  return true;
}

bool
nsObjectLoadingContent::CheckProcessPolicy(int16_t *aContentPolicy)
{
  if (!aContentPolicy) {
    NS_NOTREACHED("Null out variable");
    return false;
  }

  nsCOMPtr<nsIContent> thisContent =
    do_QueryInterface(static_cast<nsIImageLoadingContent*>(this));
  NS_ASSERTION(thisContent, "Must be an instance of content");

  nsIDocument* doc = thisContent->OwnerDoc();
  
  int32_t objectType;
  switch (mType) {
    case eType_Image:
      objectType = nsIContentPolicy::TYPE_IMAGE;
      break;
    case eType_Document:
      objectType = nsIContentPolicy::TYPE_DOCUMENT;
      break;
    case eType_Plugin:
      objectType = nsIContentPolicy::TYPE_OBJECT;
      break;
    default:
      NS_NOTREACHED("Calling checkProcessPolicy with a unloadable type");
      return false;
  }

  *aContentPolicy = nsIContentPolicy::ACCEPT;
  nsresult rv =
    NS_CheckContentProcessPolicy(objectType,
                                 mURI ? mURI : mBaseURI,
                                 doc->NodePrincipal(),
                                 static_cast<nsIImageLoadingContent*>(this),
                                 mContentType,
                                 nullptr, //extra
                                 aContentPolicy,
                                 nsContentUtils::GetContentPolicy(),
                                 nsContentUtils::GetSecurityManager());
  NS_ENSURE_SUCCESS(rv, false);

  if (NS_CP_REJECTED(*aContentPolicy)) {
    LOG(("OBJLC [%p]: CheckContentProcessPolicy rejected load", this));
    return false;
  }

  return true;
}

nsObjectLoadingContent::ParameterUpdateFlags
nsObjectLoadingContent::UpdateObjectParameters(bool aJavaURI)
{
  nsCOMPtr<nsIContent> thisContent =
    do_QueryInterface(static_cast<nsIImageLoadingContent*>(this));
  NS_ASSERTION(thisContent, "Must be an instance of content");

  uint32_t caps = GetCapabilities();
  LOG(("OBJLC [%p]: Updating object parameters", this));

  nsresult rv;
  nsAutoCString newMime;
  nsAutoString typeAttr;
  nsCOMPtr<nsIURI> newURI;
  nsCOMPtr<nsIURI> newBaseURI;
  ObjectType newType;
  bool isJava = false;
  // Set if this state can't be used to load anything, forces eType_Null
  bool stateInvalid = false;
  // Indicates what parameters changed.
  // eParamChannelChanged - means parameters that affect channel opening
  //                        decisions changed
  // eParamStateChanged -   means anything that affects what content we load
  //                        changed, even if the channel we'd open remains the
  //                        same.
  //
  // State changes outside of the channel parameters only matter if we've
  // already opened a channel or tried to instantiate content, whereas channel
  // parameter changes require re-opening the channel even if we haven't gotten
  // that far.
  nsObjectLoadingContent::ParameterUpdateFlags retval = eParamNoChange;

  ///
  /// Initial MIME Type
  ///
  if (aJavaURI || thisContent->NodeInfo()->Equals(nsGkAtoms::applet)) {
    newMime.AssignLiteral("application/x-java-vm");
    isJava = true;
  } else {
    nsAutoString rawTypeAttr;
    thisContent->GetAttr(kNameSpaceID_None, nsGkAtoms::type, rawTypeAttr);
    if (!rawTypeAttr.IsEmpty()) {
      typeAttr = rawTypeAttr;
      CopyUTF16toUTF8(rawTypeAttr, newMime);
      isJava = nsPluginHost::IsJavaMIMEType(newMime.get());
    }
  }

  ///
  /// classID
  ///

  if (caps & eSupportClassID) {
    nsAutoString classIDAttr;
    thisContent->GetAttr(kNameSpaceID_None, nsGkAtoms::classid, classIDAttr);
    if (!classIDAttr.IsEmpty()) {
      // Our classid support is limited to 'java:' ids
      if (StringBeginsWith(classIDAttr, NS_LITERAL_STRING("java:")) &&
          PluginExistsForType("application/x-java-vm")) {
        newMime.Assign("application/x-java-vm");
        isJava = true;
      } else {
        // XXX(johns): Our de-facto behavior since forever was to refuse to load
        // Objects who don't have a classid we support, regardless of other type
        // or uri info leads to a valid plugin.
        newMime.Truncate();
        stateInvalid = true;
      }
    }
  }

  ///
  /// Codebase
  ///

  nsAutoString codebaseStr;
  nsCOMPtr<nsIURI> docBaseURI = thisContent->GetBaseURI();
  bool hasCodebase = thisContent->HasAttr(kNameSpaceID_None, nsGkAtoms::codebase);
  if (hasCodebase)
    thisContent->GetAttr(kNameSpaceID_None, nsGkAtoms::codebase, codebaseStr);


  // Java wants the codebase attribute even if it occurs in <param> tags
  // XXX(johns): This duplicates a chunk of code from nsInstanceOwner, see
  //             bug 853995
  if (isJava) {
    // Find all <param> tags that are nested beneath us, but not beneath another
    // object/applet tag.
    nsCOMArray<nsIDOMElement> ourParams;
    nsCOMPtr<nsIDOMElement> mydomElement = do_QueryInterface(thisContent);

    nsCOMPtr<nsIDOMHTMLCollection> allParams;
    NS_NAMED_LITERAL_STRING(xhtml_ns, "http://www.w3.org/1999/xhtml");
    mydomElement->GetElementsByTagNameNS(xhtml_ns, NS_LITERAL_STRING("param"),
                                         getter_AddRefs(allParams));
    if (allParams) {
      uint32_t numAllParams;
      allParams->GetLength(&numAllParams);
      for (uint32_t i = 0; i < numAllParams; i++) {
        nsCOMPtr<nsIDOMNode> pnode;
        allParams->Item(i, getter_AddRefs(pnode));
        nsCOMPtr<nsIDOMElement> domelement = do_QueryInterface(pnode);
        if (domelement) {
          nsAutoString name;
          domelement->GetAttribute(NS_LITERAL_STRING("name"), name);
          name.Trim(" \n\r\t\b", true, true, false);
          if (name.EqualsIgnoreCase("codebase")) {
            // Find the first plugin element parent
            nsCOMPtr<nsIDOMNode> parent;
            nsCOMPtr<nsIDOMHTMLObjectElement> domobject;
            nsCOMPtr<nsIDOMHTMLAppletElement> domapplet;
            pnode->GetParentNode(getter_AddRefs(parent));
            while (!(domobject || domapplet) && parent) {
              domobject = do_QueryInterface(parent);
              domapplet = do_QueryInterface(parent);
              nsCOMPtr<nsIDOMNode> temp;
              parent->GetParentNode(getter_AddRefs(temp));
              parent = temp;
            }
            if (domapplet || domobject) {
              if (domapplet) {
                parent = do_QueryInterface(domapplet);
              }
              else {
                parent = do_QueryInterface(domobject);
              }
              nsCOMPtr<nsIDOMNode> mydomNode = do_QueryInterface(mydomElement);
              if (parent == mydomNode) {
                hasCodebase = true;
                domelement->GetAttribute(NS_LITERAL_STRING("value"),
                                         codebaseStr);
                codebaseStr.Trim(" \n\r\t\b", true, true, false);
              }
            }
          }
        }
      }
    }
  }

  if (isJava && hasCodebase && codebaseStr.IsEmpty()) {
    // Java treats codebase="" as "/"
    codebaseStr.AssignLiteral("/");
    // XXX(johns): This doesn't cover the case of "https:" which java would
    //             interpret as "https:///" but we interpret as this document's
    //             URI but with a changed scheme.
  } else if (isJava && !hasCodebase) {
    // Java expects a directory as the codebase, or else it will construct
    // relative URIs incorrectly :(
    codebaseStr.AssignLiteral(".");
  }

  if (!codebaseStr.IsEmpty()) {
    rv = nsContentUtils::NewURIWithDocumentCharset(getter_AddRefs(newBaseURI),
                                                   codebaseStr,
                                                   thisContent->OwnerDoc(),
                                                   docBaseURI);
    if (NS_SUCCEEDED(rv)) {
      NS_TryToSetImmutable(newBaseURI);
    } else {
      // Malformed URI
      LOG(("OBJLC [%p]: Could not parse plugin's codebase as a URI, "
           "will use document baseURI instead", this));
    }
  }

  // If we failed to build a valid URI, use the document's base URI
  if (!newBaseURI) {
    newBaseURI = docBaseURI;
  }

  ///
  /// URI
  ///

  nsAutoString uriStr;
  // Different elements keep this in various locations
  if (isJava) {
    // Applet tags and embed/object with explicit java MIMEs have src/data
    // attributes that are not meant to be parsed as URIs or opened by the
    // browser -- act as if they are null. (Setting these attributes triggers a
    // force-load, so tracking the old value to determine if they have changed
    // is not necessary.)
  } else if (thisContent->NodeInfo()->Equals(nsGkAtoms::object)) {
    thisContent->GetAttr(kNameSpaceID_None, nsGkAtoms::data, uriStr);
  } else if (thisContent->NodeInfo()->Equals(nsGkAtoms::embed)) {
    thisContent->GetAttr(kNameSpaceID_None, nsGkAtoms::src, uriStr);
  } else {
    // Applet tags should always have a java MIME type at this point
    NS_NOTREACHED("Unrecognized plugin-loading tag");
  }

  // Note that the baseURI changing could affect the newURI, even if uriStr did
  // not change.
  if (!uriStr.IsEmpty()) {
    rv = nsContentUtils::NewURIWithDocumentCharset(getter_AddRefs(newURI),
                                                   uriStr,
                                                   thisContent->OwnerDoc(),
                                                   newBaseURI);
    if (NS_SUCCEEDED(rv)) {
      NS_TryToSetImmutable(newURI);
    } else {
      stateInvalid = true;
    }
  }

  // For eAllowPluginSkipChannel tags, if we have a non-plugin type, but can get
  // a plugin type from the extension, prefer that to falling back to a channel.
  if (GetTypeOfContent(newMime) != eType_Plugin && newURI &&
      (caps & eAllowPluginSkipChannel) &&
      IsPluginEnabledByExtension(newURI, newMime)) {
    LOG(("OBJLC [%p]: Using extension as type hint (%s)", this, newMime.get()));
    if (!isJava && nsPluginHost::IsJavaMIMEType(newMime.get())) {
      return UpdateObjectParameters(true);
    }
  }

  ///
  /// Check if the original (pre-channel) content-type or URI changed, and
  /// record mOriginal{ContentType,URI}
  ///

  if ((mOriginalContentType != newMime) || !URIEquals(mOriginalURI, newURI)) {
    // These parameters changing requires re-opening the channel, so don't
    // consider the currently-open channel below
    // XXX(johns): Changing the mime type might change our decision on whether
    //             or not we load a channel, so we count changes to it as a
    //             channel parameter change for the sake of simplicity.
    retval = (ParameterUpdateFlags)(retval | eParamChannelChanged);
    LOG(("OBJLC [%p]: Channel parameters changed", this));
  }
  mOriginalContentType = newMime;
  mOriginalURI = newURI;

  ///
  /// If we have a channel, see if its MIME type should take precendence and
  /// check the final (redirected) URL
  ///

  // If we have a loaded channel and channel parameters did not change, use it
  // to determine what we would load.
  bool useChannel = mChannelLoaded && !(retval & eParamChannelChanged);
  // If we have a channel and are type loading, as opposed to having an existing
  // channel for a previous load.
  bool newChannel = useChannel && mType == eType_Loading;

  if (newChannel && mChannel) {
    nsCString channelType;
    rv = mChannel->GetContentType(channelType);
    if (NS_FAILED(rv)) {
      NS_NOTREACHED("GetContentType failed");
      stateInvalid = true;
      channelType.Truncate();
    }

    LOG(("OBJLC [%p]: Channel has a content type of %s", this, channelType.get()));

    bool binaryChannelType = false;
    if (channelType.EqualsASCII(APPLICATION_GUESS_FROM_EXT)) {
      channelType = APPLICATION_OCTET_STREAM;
      mChannel->SetContentType(channelType);
      binaryChannelType = true;
    } else if (channelType.EqualsASCII(APPLICATION_OCTET_STREAM)
               || channelType.EqualsASCII(BINARY_OCTET_STREAM)) {
      binaryChannelType = true;
    }

    // Channel can change our URI through redirection
    rv = NS_GetFinalChannelURI(mChannel, getter_AddRefs(newURI));
    if (NS_FAILED(rv)) {
      NS_NOTREACHED("NS_GetFinalChannelURI failure");
      stateInvalid = true;
    }

    ObjectType typeHint = newMime.IsEmpty() ?
                          eType_Null : GetTypeOfContent(newMime);

    //
    // In order of preference:
    //
    // 1) Perform typemustmatch check.
    //    If check is sucessful use type without further checks.
    //    If check is unsuccessful set stateInvalid to true
    // 2) Use our type hint if it matches a plugin
    // 3) If we have eAllowPluginSkipChannel, use the uri file extension if
    //    it matches a plugin
    // 4) If the channel returns a binary stream type:
    //    4a) If we have a type non-null non-document type hint, use that
    //    4b) If the uri file extension matches a plugin type, use that
    // 5) Use the channel type

    bool overrideChannelType = false;
    if (thisContent->HasAttr(kNameSpaceID_None, nsGkAtoms::typemustmatch)) {
      if (!typeAttr.LowerCaseEqualsASCII(channelType.get())) {
        stateInvalid = true;
      }
    } else if (typeHint == eType_Plugin) {
      LOG(("OBJLC [%p]: Using plugin type hint in favor of any channel type",
           this));
      overrideChannelType = true;
    } else if ((caps & eAllowPluginSkipChannel) &&
               IsPluginEnabledByExtension(newURI, newMime)) {
      LOG(("OBJLC [%p]: Using extension as type hint for "
           "eAllowPluginSkipChannel tag (%s)", this, newMime.get()));
      overrideChannelType = true;
    } else if (binaryChannelType &&
               typeHint != eType_Null && typeHint != eType_Document) {
      LOG(("OBJLC [%p]: Using type hint in favor of binary channel type",
           this));
      overrideChannelType = true;
    } else if (binaryChannelType &&
               IsPluginEnabledByExtension(newURI, newMime)) {
      LOG(("OBJLC [%p]: Using extension as type hint for binary channel (%s)",
           this, newMime.get()));
      overrideChannelType = true;
    }

    if (overrideChannelType) {
      // Set the type we'll use for dispatch on the channel.  Otherwise we could
      // end up trying to dispatch to a nsFrameLoader, which will complain that
      // it couldn't find a way to handle application/octet-stream
      nsAutoCString parsedMime, dummy;
      NS_ParseContentType(newMime, parsedMime, dummy);
      if (!parsedMime.IsEmpty()) {
        mChannel->SetContentType(parsedMime);
      }
    } else {
      newMime = channelType;
      if (nsPluginHost::IsJavaMIMEType(newMime.get())) {
        // Java does not load with a channel, and being java retroactively
        // changes how we may have interpreted the codebase to construct this
        // URI above.  Because the behavior here is more or less undefined, play
        // it safe and reject the load.
        LOG(("OBJLC [%p]: Refusing to load with channel with java MIME",
             this));
        stateInvalid = true;
      }
    }
  } else if (newChannel) {
    LOG(("OBJLC [%p]: We failed to open a channel, marking invalid", this));
    stateInvalid = true;
  }

  ///
  /// Determine final type
  ///
  // In order of preference:
  //  1) If we have attempted channel load, or set stateInvalid above, the type
  //     is always null (fallback)
  //  2) If we have a loaded channel, we grabbed its mimeType above, use that
  //     type.
  //  3) If we have a plugin type and no URI, use that type.
  //  4) If we have a plugin type and eAllowPluginSkipChannel, use that type.
  //  5) if we have a URI, set type to loading to indicate we'd need a channel
  //     to proceed.
  //  6) Otherwise, type null to indicate unloadable content (fallback)
  //

  if (stateInvalid) {
    newType = eType_Null;
    newMime.Truncate();
  } else if (newChannel) {
      // If newChannel is set above, we considered it in setting newMime
      newType = GetTypeOfContent(newMime);
      LOG(("OBJLC [%p]: Using channel type", this));
  } else if (((caps & eAllowPluginSkipChannel) || !newURI) &&
             GetTypeOfContent(newMime) == eType_Plugin) {
    newType = eType_Plugin;
    LOG(("OBJLC [%p]: Plugin type with no URI, skipping channel load", this));
  } else if (newURI) {
    // We could potentially load this if we opened a channel on mURI, indicate
    // This by leaving type as loading
    newType = eType_Loading;
  } else {
    // Unloadable - no URI, and no plugin type. Non-plugin types (images,
    // documents) always load with a channel.
    newType = eType_Null;
  }

  ///
  /// Handle existing channels
  ///

  if (useChannel && newType == eType_Loading) {
    // We decided to use a channel, and also that the previous channel is still
    // usable, so re-use the existing values.
    newType = mType;
    newMime = mContentType;
    newURI = mURI;
  } else if (useChannel && !newChannel) {
    // We have an existing channel, but did not decide to use one.
    retval = (ParameterUpdateFlags)(retval | eParamChannelChanged);
    useChannel = false;
  }

  ///
  /// Update changed values
  ///

  if (newType != mType) {
    retval = (ParameterUpdateFlags)(retval | eParamStateChanged);
    LOG(("OBJLC [%p]: Type changed from %u -> %u", this, mType, newType));
    mType = newType;
  }

  if (!URIEquals(mBaseURI, newBaseURI)) {
    if (isJava) {
      // Java bases its class loading on the base URI, so we consider the state
      // to have changed if this changes. If the object is using a relative URI,
      // mURI will have changed below regardless
      retval = (ParameterUpdateFlags)(retval | eParamStateChanged);
    }
    LOG(("OBJLC [%p]: Object effective baseURI changed", this));
    mBaseURI = newBaseURI;
  }

  if (!URIEquals(newURI, mURI)) {
    retval = (ParameterUpdateFlags)(retval | eParamStateChanged);
    LOG(("OBJLC [%p]: Object effective URI changed", this));
    mURI = newURI;
  }

  // We don't update content type when loading, as the type is not final and we
  // don't want to superfluously change between mOriginalContentType ->
  // mContentType when doing |obj.data = obj.data| with a channel and differing
  // type.
  if (mType != eType_Loading && mContentType != newMime) {
    retval = (ParameterUpdateFlags)(retval | eParamStateChanged);
    retval = (ParameterUpdateFlags)(retval | eParamContentTypeChanged);
    LOG(("OBJLC [%p]: Object effective mime type changed (%s -> %s)",
         this, mContentType.get(), newMime.get()));
    mContentType = newMime;
  }

  // If we decided to keep using info from an old channel, but also that state
  // changed, we need to invalidate it.
  if (useChannel && !newChannel && (retval & eParamStateChanged)) {
    mType = eType_Loading;
    retval = (ParameterUpdateFlags)(retval | eParamChannelChanged);
  }

  return retval;
}

// Used by PluginDocument to kick off our initial load from the already-opened
// channel.
NS_IMETHODIMP
nsObjectLoadingContent::InitializeFromChannel(nsIRequest *aChannel)
{
  LOG(("OBJLC [%p] InitializeFromChannel: %p", this, aChannel));
  if (mType != eType_Loading || mChannel) {
    // We could technically call UnloadObject() here, if consumers have a valid
    // reason for wanting to call this on an already-loaded tag.
    NS_NOTREACHED("Should not have begun loading at this point");
    return NS_ERROR_UNEXPECTED;
  }

  // Because we didn't open this channel from an initial LoadObject, we'll
  // update our parameters now, so the OnStartRequest->LoadObject doesn't
  // believe our src/type suddenly changed.
  UpdateObjectParameters();
  // But we always want to load from a channel, in this case.
  mType = eType_Loading;
  mChannel = do_QueryInterface(aChannel);
  NS_ASSERTION(mChannel, "passed a request that is not a channel");

  // OnStartRequest will now see we have a channel in the loading state, and
  // call into LoadObject. There's a possibility LoadObject will decide not to
  // load anything from a channel - it will call CloseChannel() in that case.
  return NS_OK;
}

// Only OnStartRequest should be passing the channel parameter
nsresult
nsObjectLoadingContent::LoadObject(bool aNotify,
                                   bool aForceLoad)
{
  return LoadObject(aNotify, aForceLoad, nullptr);
}

nsresult
nsObjectLoadingContent::LoadObject(bool aNotify,
                                   bool aForceLoad,
                                   nsIRequest *aLoadingChannel)
{
  nsCOMPtr<nsIContent> thisContent =
    do_QueryInterface(static_cast<nsIImageLoadingContent*>(this));
  NS_ASSERTION(thisContent, "must be a content");
  nsIDocument* doc = thisContent->OwnerDoc();
  nsresult rv = NS_OK;

  // Sanity check
  if (!InActiveDocument(thisContent)) {
    NS_NOTREACHED("LoadObject called while not bound to an active document");
    return NS_ERROR_UNEXPECTED;
  }

  // XXX(johns): In these cases, we refuse to touch our content and just
  //   remain unloaded, as per legacy behavior. It would make more sense to
  //   load fallback content initially and refuse to ever change state again.
  if (doc->IsBeingUsedAsImage() || doc->IsLoadedAsData()) {
    return NS_OK;
  }

  LOG(("OBJLC [%p]: LoadObject called, notify %u, forceload %u, channel %p",
       this, aNotify, aForceLoad, aLoadingChannel));

  // We can't re-use an already open channel, but aForceLoad may make us try
  // to load a plugin without any changes in channel state.
  if (aForceLoad && mChannelLoaded) {
    CloseChannel();
    mChannelLoaded = false;
  }

  // Save these for NotifyStateChanged();
  nsEventStates oldState = ObjectState();
  ObjectType oldType = mType;

  ParameterUpdateFlags stateChange = UpdateObjectParameters();

  if (!stateChange && !aForceLoad) {
    return NS_OK;
  }

  ///
  /// State has changed, unload existing content and attempt to load new type
  ///
  LOG(("OBJLC [%p]: LoadObject - plugin state changed (%u)",
       this, stateChange));

  // Setup fallback info. We may also change type to fallback below in case of
  // sanity/OOM/etc. errors. We default to showing alternate content
  // NOTE LoadFallback can override this in some cases
  FallbackType fallbackType = eFallbackAlternate;

  // mType can differ with GetTypeOfContent(mContentType) if we support this
  // type, but the parameters are invalid e.g. a embed tag with type "image/png"
  // but no URI -- don't show a plugin error or unknown type error in that case.
  if (mType == eType_Null && GetTypeOfContent(mContentType) == eType_Null) {
    fallbackType = eFallbackUnsupported;
  }

  // Explicit user activation should reset if the object changes content types
  if (mActivated && (stateChange & eParamContentTypeChanged)) {
    LOG(("OBJLC [%p]: Content type changed, clearing activation state", this));
    mActivated = false;
  }

  // We synchronously start/stop plugin instances below, which may spin the
  // event loop. Re-entering into the load is fine, but at that point the
  // original load call needs to abort when unwinding
  // NOTE this is located *after* the state change check, a subseqent load
  //      with no subsequently changed state will be a no-op.
  if (mIsLoading) {
    LOG(("OBJLC [%p]: Re-entering into LoadObject", this));
  }
  mIsLoading = true;
  AutoSetLoadingToFalse reentryCheck(this);

  // Unload existing content, keeping in mind stopping plugins might spin the
  // event loop. Note that we check for still-open channels below
  UnloadObject(false); // Don't reset state
  if (!mIsLoading) {
    // The event loop must've spun and re-entered into LoadObject, which
    // finished the load
    LOG(("OBJLC [%p]: Re-entered into LoadObject, aborting outer load", this));
    return NS_OK;
  }

  // Determine what's going on with our channel.
  if (stateChange & eParamChannelChanged) {
    // If the channel params changed, throw away the channel, but unset
    // mChannelLoaded so we'll still try to open a new one for this load if
    // necessary
    CloseChannel();
    mChannelLoaded = false;
  } else if (mType == eType_Null && mChannel) {
    // If we opened a channel but then failed to find a loadable state, throw it
    // away. mChannelLoaded will indicate that we tried to load a channel at one
    // point so we wont recurse
    CloseChannel();
  } else if (mType == eType_Loading && mChannel) {
    // We're still waiting on a channel load, already opened one, and
    // channel parameters didn't change
    return NS_OK;
  } else if (mChannelLoaded && mChannel != aLoadingChannel) {
    // The only time we should have a loaded channel with a changed state is
    // when the channel has just opened -- in which case this call should
    // have originated from OnStartRequest
    NS_NOTREACHED("Loading with a channel, but state doesn't make sense");
    return NS_OK;
  }

  //
  // Security checks
  //

  if (mType != eType_Null) {
    bool allowLoad = true;
    if (nsPluginHost::IsJavaMIMEType(mContentType.get())) {
      allowLoad = CheckJavaCodebase();
    }
    int16_t contentPolicy = nsIContentPolicy::ACCEPT;
    // If mChannelLoaded is set we presumably already passed load policy
    if (allowLoad && mURI && !mChannelLoaded) {
      allowLoad = CheckLoadPolicy(&contentPolicy);
    }
    // If we're loading a type now, check ProcessPolicy. Note that we may check
    // both now in the case of plugins whose type is determined before opening a
    // channel.
    if (allowLoad && mType != eType_Loading) {
      allowLoad = CheckProcessPolicy(&contentPolicy);
    }

    // Content policy implementations can mutate the DOM, check for re-entry
    if (!mIsLoading) {
      LOG(("OBJLC [%p]: We re-entered in content policy, leaving original load",
           this));
      return NS_OK;
    }

    // Load denied, switch to fallback and set disabled/suppressed if applicable
    if (!allowLoad) {
      LOG(("OBJLC [%p]: Load denied by policy", this));
      mType = eType_Null;
      if (contentPolicy == nsIContentPolicy::REJECT_TYPE) {
        // XXX(johns) This is assuming that we were rejected by
        //            nsContentBlocker, which rejects by type if permissions
        //            reject plugins
        fallbackType = eFallbackUserDisabled;
      } else {
        fallbackType = eFallbackSuppressed;
      }
    }
  }

  // If we're a plugin but shouldn't start yet, load fallback with
  // reason click-to-play instead. Items resolved as Image/Document
  // will not be checked for previews, as well as invalid plugins
  // (they will not have the mContentType set).
  FallbackType clickToPlayReason;
  if (!mActivated && (mType == eType_Null || mType == eType_Plugin) &&
      !ShouldPlay(clickToPlayReason, false)) {
    LOG(("OBJLC [%p]: Marking plugin as click-to-play", this));
    mType = eType_Null;
    fallbackType = clickToPlayReason;
  }

  if (!mActivated && mType == eType_Plugin) {
    // Object passed ShouldPlay, so it should be considered
    // activated until it changes content type
    LOG(("OBJLC [%p]: Object implicitly activated", this));
    mActivated = true;
  }

  // Sanity check: We shouldn't have any loaded resources, pending events, or
  // a final listener at this point
  if (mFrameLoader || mPendingInstantiateEvent || mInstanceOwner ||
      mPendingCheckPluginStopEvent || mFinalListener)
  {
    NS_NOTREACHED("Trying to load new plugin with existing content");
    rv = NS_ERROR_UNEXPECTED;
    return NS_OK;
  }

  // More sanity-checking:
  // If mChannel is set, mChannelLoaded should be set, and vice-versa
  if (mType != eType_Null && !!mChannel != mChannelLoaded) {
    NS_NOTREACHED("Trying to load with bad channel state");
    rv = NS_ERROR_UNEXPECTED;
    return NS_OK;
  }

  ///
  /// Attempt to load new type
  ///

  // We don't set mFinalListener until OnStartRequest has been called, to
  // prevent re-entry ugliness with CloseChannel()
  nsCOMPtr<nsIStreamListener> finalListener;
  // If we decide to synchronously spawn a plugin, we do it after firing
  // notifications to avoid re-entry causing notifications to fire out of order.
  bool doSpawnPlugin = false;
  switch (mType) {
    case eType_Image:
      if (!mChannel) {
        // We have a LoadImage() call, but UpdateObjectParameters requires a
        // channel for images, so this is not a valid state.
        NS_NOTREACHED("Attempting to load image without a channel?");
        rv = NS_ERROR_UNEXPECTED;
        break;
      }
      rv = LoadImageWithChannel(mChannel, getter_AddRefs(finalListener));
      // finalListener will receive OnStartRequest below
    break;
    case eType_Plugin:
    {
      if (mChannel) {
        // Force a sync state change now, we need the frame created
        NotifyStateChanged(oldType, oldState, true, aNotify);
        oldType = mType;
        oldState = ObjectState();

        if (!thisContent->GetPrimaryFrame()) {
          // We're un-rendered, and can't instantiate a plugin. HasNewFrame will
          // re-start us when we can proceed.
          LOG(("OBJLC [%p]: Aborting load - plugin-type, but no frame", this));
          CloseChannel();
          break;
        }

        // We'll handle this below
        doSpawnPlugin = true;
      } else {
        rv = AsyncStartPluginInstance();
      }
    }
    break;
    case eType_Document:
    {
      if (!mChannel) {
        // We could mFrameLoader->LoadURI(mURI), but UpdateObjectParameters
        // requires documents have a channel, so this is not a valid state.
        NS_NOTREACHED("Attempting to load a document without a channel");
        mType = eType_Null;
        break;
      }

      mFrameLoader = nsFrameLoader::Create(thisContent->AsElement(),
                                           mNetworkCreated);
      if (!mFrameLoader) {
        NS_NOTREACHED("nsFrameLoader::Create failed");
        mType = eType_Null;
        break;
      }

      rv = mFrameLoader->CheckForRecursiveLoad(mURI);
      if (NS_FAILED(rv)) {
        LOG(("OBJLC [%p]: Aborting recursive load", this));
        mFrameLoader->Destroy();
        mFrameLoader = nullptr;
        mType = eType_Null;
        break;
      }

      // We're loading a document, so we have to set LOAD_DOCUMENT_URI
      // (especially important for firing onload)
      nsLoadFlags flags = 0;
      mChannel->GetLoadFlags(&flags);
      flags |= nsIChannel::LOAD_DOCUMENT_URI;
      mChannel->SetLoadFlags(flags);

      nsCOMPtr<nsIDocShell> docShell;
      rv = mFrameLoader->GetDocShell(getter_AddRefs(docShell));
      if (NS_FAILED(rv)) {
        NS_NOTREACHED("Could not get DocShell from mFrameLoader?");
        mType = eType_Null;
        break;
      }

      nsCOMPtr<nsIInterfaceRequestor> req(do_QueryInterface(docShell));
      NS_ASSERTION(req, "Docshell must be an ifreq");

      nsCOMPtr<nsIURILoader>
        uriLoader(do_GetService(NS_URI_LOADER_CONTRACTID, &rv));
      if (NS_FAILED(rv)) {
        NS_NOTREACHED("Failed to get uriLoader service");
        mType = eType_Null;
        break;
      }
      rv = uriLoader->OpenChannel(mChannel, nsIURILoader::DONT_RETARGET, req,
                                  getter_AddRefs(finalListener));
      // finalListener will receive OnStartRequest below
    }
    break;
    case eType_Loading:
      // If our type remains Loading, we need a channel to proceed
      rv = OpenChannel();
      if (NS_FAILED(rv)) {
        LOG(("OBJLC [%p]: OpenChannel returned failure (%u)", this, rv));
      }
    break;
    case eType_Null:
      // Handled below, silence compiler warnings
    break;
  };

  //
  // Loaded, handle notifications and fallback
  //
  if (NS_FAILED(rv)) {
    // If we failed in the loading hunk above, switch to fallback
    LOG(("OBJLC [%p]: Loading failed, switching to fallback", this));
    mType = eType_Null;
  }

  // If we didn't load anything, handle switching to fallback state
  if (mType == eType_Null) {
    LOG(("OBJLC [%p]: Loading fallback, type %u", this, fallbackType));
    NS_ASSERTION(!mFrameLoader && !mInstanceOwner,
                 "switched to type null but also loaded something");

    if (mChannel) {
      // If we were loading with a channel but then failed over, throw it away
      CloseChannel();
    }

    // Don't try to initialize plugins or final listener below
    doSpawnPlugin = false;
    finalListener = nullptr;

    // Don't notify, as LoadFallback doesn't know of our previous state
    // (so really this is just setting mFallbackType)
    LoadFallback(fallbackType, false);
  }

  // Notify of our final state
  NotifyStateChanged(oldType, oldState, false, aNotify);
  NS_ENSURE_TRUE(mIsLoading, NS_OK);


  //
  // Spawning plugins and dispatching to the final listener may re-enter, so are
  // delayed until after we fire a notification, to prevent missing
  // notifications or firing them out of order.
  //
  // Note that we ensured that we entered into LoadObject() from
  // ::OnStartRequest above when loading with a channel.
  //

  rv = NS_OK;
  if (doSpawnPlugin) {
    rv = InstantiatePluginInstance(true);
    NS_ENSURE_TRUE(mIsLoading, NS_OK);
    // Create the final listener if we're loading with a channel. We can't do
    // this in the loading block above as it requires an instance.
    if (aLoadingChannel && NS_SUCCEEDED(rv)) {
      if (NS_SUCCEEDED(rv) && MakePluginListener()) {
        rv = mFinalListener->OnStartRequest(mChannel, nullptr);
        if (NS_FAILED(rv)) {
          // Plugins can reject their initial stream, but continue to run.
          CloseChannel();
          NS_ENSURE_TRUE(mIsLoading, NS_OK);
          rv = NS_OK;
        }
      }
    }
  } else if (finalListener) {
    NS_ASSERTION(mType != eType_Null && mType != eType_Loading,
                 "We should not have a final listener with a non-loaded type");
    mFinalListener = finalListener;
    rv = finalListener->OnStartRequest(mChannel, nullptr);
  }

  if (NS_FAILED(rv) && mIsLoading) {
    // Since we've already notified of our transition, we can just Unload and
    // call LoadFallback (which will notify again)
    mType = eType_Null;
    UnloadObject(false);
    NS_ENSURE_TRUE(mIsLoading, NS_OK);
    CloseChannel();
    LoadFallback(fallbackType, true);
  }

  return NS_OK;
}

// This call can re-enter when dealing with plugin listeners
nsresult
nsObjectLoadingContent::CloseChannel()
{
  if (mChannel) {
    LOG(("OBJLC [%p]: Closing channel\n", this));
    // Null the values before potentially-reentering, and ensure they survive
    // the call
    nsCOMPtr<nsIChannel> channelGrip(mChannel);
    nsCOMPtr<nsIStreamListener> listenerGrip(mFinalListener);
    mChannel = nullptr;
    mFinalListener = nullptr;
    channelGrip->Cancel(NS_BINDING_ABORTED);
    if (listenerGrip) {
      // mFinalListener is only set by LoadObject after OnStartRequest, or
      // by OnStartRequest in the case of late-opened plugin streams
      listenerGrip->OnStopRequest(channelGrip, nullptr, NS_BINDING_ABORTED);
    }
  }
  return NS_OK;
}

nsresult
nsObjectLoadingContent::OpenChannel()
{
  nsCOMPtr<nsIContent> thisContent =
    do_QueryInterface(static_cast<nsIImageLoadingContent*>(this));
  nsCOMPtr<nsIScriptSecurityManager> secMan =
    nsContentUtils::GetSecurityManager();
  NS_ASSERTION(thisContent, "must be a content");
  nsIDocument* doc = thisContent->OwnerDoc();
  NS_ASSERTION(doc, "No owner document?");

  nsresult rv;
  mChannel = nullptr;

  // E.g. mms://
  if (!mURI || !CanHandleURI(mURI)) {
    return NS_ERROR_NOT_AVAILABLE;
  }

  rv = secMan->CheckLoadURIWithPrincipal(thisContent->NodePrincipal(), mURI, 0);
  NS_ENSURE_SUCCESS(rv, rv);

  nsCOMPtr<nsILoadGroup> group = doc->GetDocumentLoadGroup();
  nsCOMPtr<nsIChannel> chan;
  nsCOMPtr<nsIChannelPolicy> channelPolicy;
  nsCOMPtr<nsIContentSecurityPolicy> csp;
  rv = doc->NodePrincipal()->GetCsp(getter_AddRefs(csp));
  NS_ENSURE_SUCCESS(rv, rv);
  if (csp) {
    channelPolicy = do_CreateInstance("@mozilla.org/nschannelpolicy;1");
    channelPolicy->SetContentSecurityPolicy(csp);
    channelPolicy->SetLoadType(nsIContentPolicy::TYPE_OBJECT);
  }
  nsRefPtr<ObjectInterfaceRequestorShim> shim =
    new ObjectInterfaceRequestorShim(this);
  rv = NS_NewChannel(getter_AddRefs(chan), mURI, nullptr, group, shim,
                     nsIChannel::LOAD_CALL_CONTENT_SNIFFERS |
                     nsIChannel::LOAD_CLASSIFY_URI,
                     channelPolicy);
  NS_ENSURE_SUCCESS(rv, rv);

  // Referrer
  nsCOMPtr<nsIHttpChannel> httpChan(do_QueryInterface(chan));
  if (httpChan) {
    httpChan->SetReferrer(doc->GetDocumentURI());
  }

  // Set up the channel's principal and such, like nsDocShell::DoURILoad does.
  // If the content being loaded should be sandboxed with respect to origin we
  // create a new null principal here. nsContentUtils::SetUpChannelOwner is
  // used with a flag to force it to be set as the channel owner.
  nsCOMPtr<nsIPrincipal> ownerPrincipal;
  uint32_t sandboxFlags = doc->GetSandboxFlags();
  if (sandboxFlags & SANDBOXED_ORIGIN) {
    ownerPrincipal = do_CreateInstance("@mozilla.org/nullprincipal;1");
  } else {
    // Not sandboxed - we allow the content to assume its natural owner.
    ownerPrincipal = thisContent->NodePrincipal();
  }
  nsContentUtils::SetUpChannelOwner(ownerPrincipal, chan, mURI, true,
                                    sandboxFlags & SANDBOXED_ORIGIN);

  nsCOMPtr<nsIScriptChannel> scriptChannel = do_QueryInterface(chan);
  if (scriptChannel) {
    // Allow execution against our context if the principals match
    scriptChannel->SetExecutionPolicy(nsIScriptChannel::EXECUTE_NORMAL);
  }

  // AsyncOpen can fail if a file does not exist.
  rv = chan->AsyncOpen(shim, nullptr);
  NS_ENSURE_SUCCESS(rv, rv);
  LOG(("OBJLC [%p]: Channel opened", this));
  mChannel = chan;
  return NS_OK;
}

uint32_t
nsObjectLoadingContent::GetCapabilities() const
{
  return eSupportImages |
         eSupportPlugins |
         eSupportDocuments |
         eSupportSVG;
}

void
nsObjectLoadingContent::DestroyContent()
{
  if (mFrameLoader) {
    mFrameLoader->Destroy();
    mFrameLoader = nullptr;
  }

  QueueCheckPluginStopEvent();
}

/* static */
void
nsObjectLoadingContent::Traverse(nsObjectLoadingContent *tmp,
                                 nsCycleCollectionTraversalCallback &cb)
{
  NS_CYCLE_COLLECTION_NOTE_EDGE_NAME(cb, "mFrameLoader");
  cb.NoteXPCOMChild(static_cast<nsIFrameLoader*>(tmp->mFrameLoader));
}

void
nsObjectLoadingContent::UnloadObject(bool aResetState)
{
  // Don't notify in CancelImageRequests until we transition to a new loaded
  // state
  CancelImageRequests(false);
  if (mFrameLoader) {
    mFrameLoader->Destroy();
    mFrameLoader = nullptr;
  }

  if (aResetState) {
    if (mType != eType_Plugin) {
      // This can re-enter when dealing with plugins, and StopPluginInstance
      // will handle it
      CloseChannel();
    }
    mChannelLoaded = false;
    mType = eType_Loading;
    mURI = mOriginalURI = mBaseURI = nullptr;
    mContentType.Truncate();
    mOriginalContentType.Truncate();
  }

  // InstantiatePluginInstance checks this after re-entrant calls and aborts if
  // it was cleared from under it
  mInstantiating = false;

  mScriptRequested = false;

  if (!mInstanceOwner) {
    // The protochain is normally thrown out after a plugin stops, but if we
    // re-enter while stopping a plugin and try to load something new, we need
    // to throw away the old protochain in the nested unload.
    TeardownProtoChain();
    mIsStopping = false;
  }

  // This call should be last as it may re-enter
  StopPluginInstance();
}

void
nsObjectLoadingContent::NotifyStateChanged(ObjectType aOldType,
                                           nsEventStates aOldState,
                                           bool aSync,
                                           bool aNotify)
{
  LOG(("OBJLC [%p]: Notifying about state change: (%u, %llx) -> (%u, %llx)"
       " (sync %i, notify %i)", this, aOldType, aOldState.GetInternalValue(),
       mType, ObjectState().GetInternalValue(), aSync, aNotify));

  nsCOMPtr<nsIContent> thisContent = 
    do_QueryInterface(static_cast<nsIImageLoadingContent*>(this));
  NS_ASSERTION(thisContent, "must be a content");

  NS_ASSERTION(thisContent->IsElement(), "Not an element?");

  // XXX(johns): A good bit of the code below replicates UpdateState(true)

  // Unfortunately, we do some state changes without notifying
  // (e.g. in Fallback when canceling image requests), so we have to
  // manually notify object state changes.
  thisContent->AsElement()->UpdateState(false);

  if (!aNotify) {
    // We're done here
    return;
  }

  nsIDocument* doc = thisContent->GetCurrentDoc();
  if (!doc) {
    return; // Nothing to do
  }

  nsEventStates newState = ObjectState();

  if (newState != aOldState) {
    // This will trigger frame construction
    NS_ASSERTION(InActiveDocument(thisContent), "Something is confused");
    nsEventStates changedBits = aOldState ^ newState;

    {
      nsAutoScriptBlocker scriptBlocker;
      doc->ContentStateChanged(thisContent, changedBits);
    }
    if (aSync) {
      // Make sure that frames are actually constructed immediately.
      doc->FlushPendingNotifications(Flush_Frames);
    }
  } else if (aOldType != mType) {
    // If our state changed, then we already recreated frames
    // Otherwise, need to do that here
    nsCOMPtr<nsIPresShell> shell = doc->GetShell();
    if (shell) {
      shell->RecreateFramesFor(thisContent);
    }
  }
}

nsObjectLoadingContent::ObjectType
nsObjectLoadingContent::GetTypeOfContent(const nsCString& aMIMEType)
{
  if (aMIMEType.IsEmpty()) {
    return eType_Null;
  }

  uint32_t caps = GetCapabilities();

  if ((caps & eSupportImages) && IsSupportedImage(aMIMEType)) {
    return eType_Image;
  }

  // SVGs load as documents, but are their own capability
  bool isSVG = aMIMEType.LowerCaseEqualsLiteral("image/svg+xml");
  Capabilities supportType = isSVG ? eSupportSVG : eSupportDocuments;
  if ((caps & supportType) && IsSupportedDocument(aMIMEType)) {
    return eType_Document;
  }

  if (caps & eSupportPlugins && PluginExistsForType(aMIMEType.get())) {
    // ShouldPlay will handle checking for disabled plugins
    return eType_Plugin;
  }

  return eType_Null;
}

nsObjectFrame*
nsObjectLoadingContent::GetExistingFrame()
{
  nsCOMPtr<nsIContent> thisContent = do_QueryInterface(static_cast<nsIImageLoadingContent*>(this));
  nsIFrame* frame = thisContent->GetPrimaryFrame();
  nsIObjectFrame* objFrame = do_QueryFrame(frame);
  return static_cast<nsObjectFrame*>(objFrame);
}

void
nsObjectLoadingContent::CreateStaticClone(nsObjectLoadingContent* aDest) const
{
  nsImageLoadingContent::CreateStaticImageClone(aDest);

  aDest->mType = mType;
  nsObjectLoadingContent* thisObj = const_cast<nsObjectLoadingContent*>(this);
  if (thisObj->mPrintFrame.IsAlive()) {
    aDest->mPrintFrame = thisObj->mPrintFrame;
  } else {
    aDest->mPrintFrame = const_cast<nsObjectLoadingContent*>(this)->GetExistingFrame();
  }

  if (mFrameLoader) {
    nsCOMPtr<nsIContent> content =
      do_QueryInterface(static_cast<nsIImageLoadingContent*>(aDest));
    nsFrameLoader* fl = nsFrameLoader::Create(content->AsElement(), false);
    if (fl) {
      aDest->mFrameLoader = fl;
      mFrameLoader->CreateStaticClone(fl);
    }
  }
}

NS_IMETHODIMP
nsObjectLoadingContent::GetPrintFrame(nsIFrame** aFrame)
{
  *aFrame = mPrintFrame.GetFrame();
  return NS_OK;
}

NS_IMETHODIMP
nsObjectLoadingContent::PluginDestroyed()
{
  // Called when our plugin is destroyed from under us, usually when reloading
  // plugins in plugin host. Invalidate instance owner / prototype but otherwise
  // don't take any action.
  TeardownProtoChain();
  mInstanceOwner->Destroy();
  mInstanceOwner = nullptr;
  return NS_OK;
}

NS_IMETHODIMP
nsObjectLoadingContent::PluginCrashed(nsIPluginTag* aPluginTag,
                                      const nsAString& pluginDumpID,
                                      const nsAString& browserDumpID,
                                      bool submittedCrashReport)
{
  LOG(("OBJLC [%p]: Plugin Crashed, queuing crash event", this));
  NS_ASSERTION(mType == eType_Plugin, "PluginCrashed at non-plugin type");

  PluginDestroyed();

  // Switch to fallback/crashed state, notify
  LoadFallback(eFallbackCrashed, true);

  // send nsPluginCrashedEvent
  nsCOMPtr<nsIContent> thisContent =
    do_QueryInterface(static_cast<nsIImageLoadingContent*>(this));

  // Note that aPluginTag in invalidated after we're called, so copy 
  // out any data we need now.
  nsAutoCString pluginName;
  aPluginTag->GetName(pluginName);
  nsAutoCString pluginFilename;
  aPluginTag->GetFilename(pluginFilename);

  nsCOMPtr<nsIRunnable> ev =
    new nsPluginCrashedEvent(thisContent,
                             pluginDumpID,
                             browserDumpID,
                             NS_ConvertUTF8toUTF16(pluginName),
                             NS_ConvertUTF8toUTF16(pluginFilename),
                             submittedCrashReport);
  nsresult rv = NS_DispatchToCurrentThread(ev);
  if (NS_FAILED(rv)) {
    NS_WARNING("failed to dispatch nsPluginCrashedEvent");
  }
  return NS_OK;
}

nsresult
nsObjectLoadingContent::ScriptRequestPluginInstance(JSContext* aCx,
                                                    nsNPAPIPluginInstance **aResult)
{
  // The below methods pull the cx off the stack, so make sure they match.
  //
  // NB: Sometimes there's a null cx on the stack, in which case |cx| is the
  // safe JS context. But in that case, IsCallerChrome() will return true,
  // so the ensuing expression is short-circuited.
  MOZ_ASSERT_IF(nsContentUtils::GetCurrentJSContext(),
                aCx == nsContentUtils::GetCurrentJSContext());
  bool callerIsContentJS = (!nsContentUtils::IsCallerChrome() &&
                            !nsContentUtils::IsCallerXBL() &&
                            js::IsContextRunningJS(aCx));

  nsCOMPtr<nsIContent> thisContent =
    do_QueryInterface(static_cast<nsIImageLoadingContent*>(this));

  *aResult = nullptr;

  // The first time content script attempts to access placeholder content, fire
  // an event.  Fallback types >= eFallbackClickToPlay are plugin-replacement
  // types, see header.
  if (callerIsContentJS && !mScriptRequested &&
      InActiveDocument(thisContent) && mType == eType_Null &&
      mFallbackType >= eFallbackClickToPlay) {
    nsCOMPtr<nsIRunnable> ev =
      new nsSimplePluginEvent(thisContent,
                              NS_LITERAL_STRING("PluginScripted"));
    nsresult rv = NS_DispatchToCurrentThread(ev);
    if (NS_FAILED(rv)) {
      NS_NOTREACHED("failed to dispatch PluginScripted event");
    }
    mScriptRequested = true;
  } else if (callerIsContentJS && mType == eType_Plugin && !mInstanceOwner &&
             nsContentUtils::IsSafeToRunScript() &&
             InActiveDocument(thisContent)) {
    // If we're configured as a plugin in an active document and it's safe to
    // run scripts right now, try spawning synchronously
    SyncStartPluginInstance();
  }

  if (mInstanceOwner) {
    return mInstanceOwner->GetInstance(aResult);
  }

  // Note that returning a null plugin is expected (and happens often)
  return NS_OK;
}

NS_IMETHODIMP
nsObjectLoadingContent::SyncStartPluginInstance()
{
  NS_ASSERTION(nsContentUtils::IsSafeToRunScript(),
               "Must be able to run script in order to instantiate a plugin instance!");

  // Don't even attempt to start an instance unless the content is in
  // the document and active
  nsCOMPtr<nsIContent> thisContent =
    do_QueryInterface(static_cast<nsIImageLoadingContent*>(this));
  if (!InActiveDocument(thisContent)) {
    return NS_ERROR_FAILURE;
  }

  nsCOMPtr<nsIURI> kungFuURIGrip(mURI);
  nsCString contentType(mContentType);
  return InstantiatePluginInstance();
}

NS_IMETHODIMP
nsObjectLoadingContent::AsyncStartPluginInstance()
{
  // OK to have an instance already or a pending spawn.
  if (mInstanceOwner || mPendingInstantiateEvent) {
    return NS_OK;
  }

  nsCOMPtr<nsIContent> thisContent =
    do_QueryInterface(static_cast<nsIImageLoadingContent*>(this));
  nsIDocument* doc = thisContent->OwnerDoc();
  if (doc->IsStaticDocument() || doc->IsBeingUsedAsImage()) {
    return NS_OK;
  }

  nsCOMPtr<nsIRunnable> event = new nsAsyncInstantiateEvent(this);
  if (!event) {
    return NS_ERROR_OUT_OF_MEMORY;
  }
  nsresult rv = NS_DispatchToCurrentThread(event);
  if (NS_SUCCEEDED(rv)) {
    // Track pending events
    mPendingInstantiateEvent = event;
  }

  return rv;
}

NS_IMETHODIMP
nsObjectLoadingContent::GetSrcURI(nsIURI** aURI)
{
  NS_IF_ADDREF(*aURI = GetSrcURI());
  return NS_OK;
}

static bool
DoDelayedStop(nsPluginInstanceOwner* aInstanceOwner,
              nsObjectLoadingContent* aContent,
              bool aDelayedStop)
{
  // Don't delay stopping QuickTime (bug 425157), Flip4Mac (bug 426524),
  // XStandard (bug 430219), CMISS Zinc (bug 429604).
  if (aDelayedStop
#if !(defined XP_WIN || defined MOZ_X11)
      && !aInstanceOwner->MatchPluginName("QuickTime")
      && !aInstanceOwner->MatchPluginName("Flip4Mac")
      && !aInstanceOwner->MatchPluginName("XStandard plugin")
      && !aInstanceOwner->MatchPluginName("CMISS Zinc Plugin")
#endif
      ) {
    nsCOMPtr<nsIRunnable> evt =
      new nsStopPluginRunnable(aInstanceOwner, aContent);
    NS_DispatchToCurrentThread(evt);
    return true;
  }
  return false;
}

void
nsObjectLoadingContent::LoadFallback(FallbackType aType, bool aNotify) {
  nsEventStates oldState = ObjectState();
  ObjectType oldType = mType;

  NS_ASSERTION(!mInstanceOwner && !mFrameLoader && !mChannel,
               "LoadFallback called with loaded content");

  //
  // Fixup mFallbackType
  //
  nsCOMPtr<nsIContent> thisContent =
  do_QueryInterface(static_cast<nsIImageLoadingContent*>(this));
  NS_ASSERTION(thisContent, "must be a content");

  if (!thisContent->IsHTML() || mContentType.IsEmpty()) {
    // Don't let custom fallback handlers run outside HTML, tags without a
    // determined type should always just be alternate content
    aType = eFallbackAlternate;
  }

  if (thisContent->Tag() == nsGkAtoms::object &&
      (aType == eFallbackUnsupported ||
       aType == eFallbackDisabled ||
       aType == eFallbackBlocklisted))
  {
    // Show alternate content instead, if it exists
    for (nsIContent* child = thisContent->GetFirstChild();
         child; child = child->GetNextSibling()) {
      if (!child->IsHTML(nsGkAtoms::param) &&
          nsStyleUtil::IsSignificantChild(child, true, false)) {
        aType = eFallbackAlternate;
        break;
      }
    }
  }

  mType = eType_Null;
  mFallbackType = aType;

  // Notify
  if (!aNotify) {
    return; // done
  }

  NotifyStateChanged(oldType, oldState, false, true);
}

void
nsObjectLoadingContent::DoStopPlugin(nsPluginInstanceOwner* aInstanceOwner,
                                     bool aDelayedStop,
                                     bool aForcedReentry)
{
  // DoStopPlugin can process events -- There may be pending
  // CheckPluginStopEvent events which can drop in underneath us and destroy the
  // instance we are about to destroy. We prevent that with the mPluginStopping
  // flag.  (aForcedReentry is only true from the callback of an earlier delayed
  // stop)
  if (mIsStopping && !aForcedReentry) {
    return;
  }
  mIsStopping = true;

  nsRefPtr<nsPluginInstanceOwner> kungFuDeathGrip(aInstanceOwner);
  nsRefPtr<nsNPAPIPluginInstance> inst;
  aInstanceOwner->GetInstance(getter_AddRefs(inst));
  if (inst) {
    if (DoDelayedStop(aInstanceOwner, this, aDelayedStop)) {
      return;
    }

#if defined(XP_MACOSX)
    aInstanceOwner->HidePluginWindow();
#endif

    nsRefPtr<nsPluginHost> pluginHost = nsPluginHost::GetInst();
    NS_ASSERTION(pluginHost, "No plugin host?");
    pluginHost->StopPluginInstance(inst);
  }

  aInstanceOwner->Destroy();

  // If we re-enter in plugin teardown UnloadObject will tear down the
  // protochain -- the current protochain could be from a new, unrelated, load.
  if (!mIsStopping) {
    LOG(("OBJLC [%p]: Re-entered in plugin teardown", this));
    return;
  }

  TeardownProtoChain();
  mIsStopping = false;
}

NS_IMETHODIMP
nsObjectLoadingContent::StopPluginInstance()
{
  // Clear any pending events
  mPendingInstantiateEvent = nullptr;
  mPendingCheckPluginStopEvent = nullptr;

  if (!mInstanceOwner) {
    return NS_OK;
  }

  if (mChannel) {
    // The plugin has already used data from this channel, we'll need to
    // re-open it to handle instantiating again, even if we don't invalidate
    // our loaded state.
    /// XXX(johns): Except currently, we don't, just leaving re-opening channels
    ///             to plugins...
    LOG(("OBJLC [%p]: StopPluginInstance - Closing used channel", this));
    CloseChannel();
  }

  // We detach the instance owner's frame before destruction, but don't destroy
  // the instance owner until the plugin is stopped.
  mInstanceOwner->SetFrame(nullptr);

  bool delayedStop = false;
#ifdef XP_WIN
  // Force delayed stop for Real plugin only; see bug 420886, 426852.
  nsRefPtr<nsNPAPIPluginInstance> inst;
  mInstanceOwner->GetInstance(getter_AddRefs(inst));
  if (inst) {
    const char* mime = nullptr;
    if (NS_SUCCEEDED(inst->GetMIMEType(&mime)) && mime) {
      if (strcmp(mime, "audio/x-pn-realaudio-plugin") == 0) {
        delayedStop = true;
      }
    }
  }
#endif

  nsRefPtr<nsPluginInstanceOwner> ownerGrip(mInstanceOwner);
  mInstanceOwner = nullptr;

  // This can/will re-enter
  DoStopPlugin(ownerGrip, delayedStop);

  return NS_OK;
}

void
nsObjectLoadingContent::NotifyContentObjectWrapper()
{
  nsCOMPtr<nsIContent> thisContent =
    do_QueryInterface(static_cast<nsIImageLoadingContent*>(this));

  nsCOMPtr<nsIDocument> doc = thisContent->GetDocument();
  if (!doc)
    return;

  nsCOMPtr<nsIScriptGlobalObject> sgo =  do_QueryInterface(doc->GetScopeObject());
  if (!sgo)
    return;

  nsIScriptContext *scx = sgo->GetContext();
  if (!scx)
    return;

  JSContext *cx = scx->GetNativeContext();
  nsCxPusher pusher;
  pusher.Push(cx);

  JS::Rooted<JSObject*> obj(cx, thisContent->GetWrapper());
  if (!obj) {
    // Nothing to do here if there's no wrapper for mContent. The proto
    // chain will be fixed appropriately when the wrapper is created.
    return;
  }

  SetupProtoChain(cx, obj);
}

NS_IMETHODIMP
nsObjectLoadingContent::PlayPlugin()
{
  if (!nsContentUtils::IsCallerChrome())
    return NS_OK;

  if (!mActivated) {
    mActivated = true;
    LOG(("OBJLC [%p]: Activated by user", this));
  }

  // If we're in a click-to-play or play preview state, we need to reload
  // Fallback types >= eFallbackClickToPlay are plugin-replacement types, see
  // header
  if (mType == eType_Null && mFallbackType >= eFallbackClickToPlay) {
    return LoadObject(true, true);
  }

  return NS_OK;
}

NS_IMETHODIMP
nsObjectLoadingContent::Reload(bool aClearActivation)
{
  if (aClearActivation) {
    mActivated = false;
    mPlayPreviewCanceled = false;
  }

  return LoadObject(true, true);
}

NS_IMETHODIMP
nsObjectLoadingContent::GetActivated(bool *aActivated)
{
  *aActivated = Activated();
  return NS_OK;
}

NS_IMETHODIMP
nsObjectLoadingContent::GetPluginFallbackType(uint32_t* aPluginFallbackType)
{
  NS_ENSURE_TRUE(nsContentUtils::IsCallerChrome(), NS_ERROR_NOT_AVAILABLE);
  *aPluginFallbackType = mFallbackType;
  return NS_OK;
}

uint32_t
nsObjectLoadingContent::DefaultFallbackType()
{
  FallbackType reason;
  bool go = ShouldPlay(reason, true);
  if (go) {
    return PLUGIN_ACTIVE;
  }
  return reason;
}

NS_IMETHODIMP
nsObjectLoadingContent::GetHasRunningPlugin(bool *aHasPlugin)
{
  NS_ENSURE_TRUE(nsContentUtils::IsCallerChrome(), NS_ERROR_NOT_AVAILABLE);
  *aHasPlugin = HasRunningPlugin();
  return NS_OK;
}

NS_IMETHODIMP
nsObjectLoadingContent::CancelPlayPreview()
{
  if (!nsContentUtils::IsCallerChrome())
    return NS_ERROR_NOT_AVAILABLE;

  mPlayPreviewCanceled = true;

  // If we're in play preview state already, reload
  if (mType == eType_Null && mFallbackType == eFallbackPlayPreview) {
    return LoadObject(true, true);
  }

  return NS_OK;
}

static bool sPrefsInitialized;
static uint32_t sSessionTimeoutMinutes;
static uint32_t sPersistentTimeoutDays;

bool
nsObjectLoadingContent::ShouldPlay(FallbackType &aReason, bool aIgnoreCurrentType)
{
  nsresult rv;

  if (!sPrefsInitialized) {
    Preferences::AddUintVarCache(&sSessionTimeoutMinutes,
                                 "plugin.sessionPermissionNow.intervalInMinutes", 60);
    Preferences::AddUintVarCache(&sPersistentTimeoutDays,
                                 "plugin.persistentPermissionAlways.intervalInDays", 90);
    sPrefsInitialized = true;
  }

  nsRefPtr<nsPluginHost> pluginHost = nsPluginHost::GetInst();

  nsCOMPtr<nsIPluginPlayPreviewInfo> playPreviewInfo;
  bool isPlayPreviewSpecified = NS_SUCCEEDED(pluginHost->GetPlayPreviewInfo(
    mContentType, getter_AddRefs(playPreviewInfo)));
  bool ignoreCTP = false;
  if (isPlayPreviewSpecified) {
    playPreviewInfo->GetIgnoreCTP(&ignoreCTP);
  }
  if (isPlayPreviewSpecified && !mPlayPreviewCanceled &&
      ignoreCTP) {
    // play preview in ignoreCTP mode is shown even if the native plugin
    // is not present/installed
    aReason = eFallbackPlayPreview;
    return false;
  }
  // at this point if it's not a plugin, we let it play/fallback
  if (!aIgnoreCurrentType && mType != eType_Plugin) {
    return true;
  }

  // Order of checks:
  // * Assume a default of click-to-play
  // * If globally disabled, per-site permissions cannot override.
  // * If blocklisted, override the reason with the blocklist reason
  // * If not blocklisted but playPreview, override the reason with the
  //   playPreview reason.
  // * Check per-site permissions and follow those if specified.
  // * Honor per-plugin disabled permission
  // * Blocklisted plugins are forced to CtP
  // * Check per-plugin permission and follow that.

  aReason = eFallbackClickToPlay;

  uint32_t enabledState = nsIPluginTag::STATE_DISABLED;
  pluginHost->GetStateForType(mContentType, &enabledState);
  if (nsIPluginTag::STATE_DISABLED == enabledState) {
    aReason = eFallbackDisabled;
    return false;
  }

  // Before we check permissions, get the blocklist state of this plugin to set
  // the fallback reason correctly.
  uint32_t blocklistState = nsIBlocklistService::STATE_NOT_BLOCKED;
  pluginHost->GetBlocklistStateForType(mContentType.get(), &blocklistState);
  if (blocklistState == nsIBlocklistService::STATE_BLOCKED) {
    // no override possible
    aReason = eFallbackBlocklisted;
    return false;
  }

  if (blocklistState == nsIBlocklistService::STATE_VULNERABLE_UPDATE_AVAILABLE) {
    aReason = eFallbackVulnerableUpdatable;
  }
  else if (blocklistState == nsIBlocklistService::STATE_VULNERABLE_NO_UPDATE) {
    aReason = eFallbackVulnerableNoUpdate;
  }

  if (aReason == eFallbackClickToPlay && isPlayPreviewSpecified &&
      !mPlayPreviewCanceled && !ignoreCTP) {
    // play preview in click-to-play mode is shown instead of standard CTP UI
    aReason = eFallbackPlayPreview;
  }

  // Check the permission manager for permission based on the principal of
  // the toplevel content.

  nsCOMPtr<nsIContent> thisContent = do_QueryInterface(static_cast<nsIObjectLoadingContent*>(this));
  MOZ_ASSERT(thisContent);
  nsIDocument* ownerDoc = thisContent->OwnerDoc();

  nsCOMPtr<nsIDOMWindow> window = ownerDoc->GetWindow();
  if (!window) {
    return false;
  }
  nsCOMPtr<nsIDOMWindow> topWindow;
  rv = window->GetTop(getter_AddRefs(topWindow));
  NS_ENSURE_SUCCESS(rv, false);
  nsCOMPtr<nsIDOMDocument> topDocument;
  rv = topWindow->GetDocument(getter_AddRefs(topDocument));
  NS_ENSURE_SUCCESS(rv, false);
  nsCOMPtr<nsIDocument> topDoc = do_QueryInterface(topDocument);

  nsCOMPtr<nsIPermissionManager> permissionManager = do_GetService(NS_PERMISSIONMANAGER_CONTRACTID, &rv);
  NS_ENSURE_SUCCESS(rv, false);

  // For now we always say that the system principal uses click-to-play since
  // that maintains current behavior and we have tests that expect this.
  // What we really should do is disable plugins entirely in pages that use
  // the system principal, i.e. in chrome pages. That way the click-to-play
  // code here wouldn't matter at all. Bug 775301 is tracking this.
  if (!nsContentUtils::IsSystemPrincipal(topDoc->NodePrincipal())) {
    nsAutoCString permissionString;
    rv = pluginHost->GetPermissionStringForType(mContentType, permissionString);
    NS_ENSURE_SUCCESS(rv, false);
    uint32_t permission;
    rv = permissionManager->TestPermissionFromPrincipal(topDoc->NodePrincipal(),
                                                        permissionString.Data(),
                                                        &permission);
    NS_ENSURE_SUCCESS(rv, false);
    if (permission != nsIPermissionManager::UNKNOWN_ACTION) {
      uint64_t nowms = PR_Now() / 1000;
      permissionManager->UpdateExpireTime(
        topDoc->NodePrincipal(), permissionString.Data(), false,
        nowms + sSessionTimeoutMinutes * 60 * 1000,
        nowms / 1000 + uint64_t(sPersistentTimeoutDays) * 24 * 60 * 60 * 1000);
    }
    switch (permission) {
    case nsIPermissionManager::ALLOW_ACTION:
      return true;
    case nsIPermissionManager::DENY_ACTION:
      aReason = eFallbackDisabled;
      return false;
    case nsIPermissionManager::PROMPT_ACTION:
      return false;
    case nsIPermissionManager::UNKNOWN_ACTION:
      break;
    default:
      MOZ_ASSERT(false);
      return false;
    }
  }

  // No site-specific permissions. Vulnerable plugins are automatically CtP
  if (blocklistState == nsIBlocklistService::STATE_VULNERABLE_UPDATE_AVAILABLE ||
      blocklistState == nsIBlocklistService::STATE_VULNERABLE_NO_UPDATE) {
    return false;
  }

  switch (enabledState) {
  case nsIPluginTag::STATE_ENABLED:
    return true;
  case nsIPluginTag::STATE_CLICKTOPLAY:
    return false;
  }
  MOZ_CRASH("Unexpected enabledState");
}

nsIDocument*
nsObjectLoadingContent::GetContentDocument()
{
  nsCOMPtr<nsIContent> thisContent =
    do_QueryInterface(static_cast<nsIImageLoadingContent*>(this));

  if (!thisContent->IsInDoc()) {
    return nullptr;
  }

  // XXXbz should this use GetCurrentDoc()?  sXBL/XBL2 issue!
  nsIDocument *sub_doc = thisContent->OwnerDoc()->GetSubDocumentFor(thisContent);
  if (!sub_doc) {
    return nullptr;
  }

  // Return null for cross-origin contentDocument.
  if (!nsContentUtils::GetSubjectPrincipal()->SubsumesConsideringDomain(sub_doc->NodePrincipal())) {
    return nullptr;
  }

  return sub_doc;
}

JS::Value
nsObjectLoadingContent::LegacyCall(JSContext* aCx,
                                   JS::Handle<JS::Value> aThisVal,
                                   const Sequence<JS::Value>& aArguments,
                                   ErrorResult& aRv)
{
  nsCOMPtr<nsIContent> thisContent =
    do_QueryInterface(static_cast<nsIImageLoadingContent*>(this));
  JS::Rooted<JSObject*> obj(aCx, thisContent->GetWrapper());
  MOZ_ASSERT(obj, "How did we get called?");

  // Make sure we're not dealing with an Xray.  Our DoCall code can't handle
  // random cross-compartment wrappers, so we're going to have to wrap
  // everything up into our compartment, but that means we need to check that
  // this is not an Xray situation by hand.
  if (!JS_WrapObject(aCx, &obj)) {
    aRv.Throw(NS_ERROR_UNEXPECTED);
    return JS::UndefinedValue();
  }

  if (nsDOMClassInfo::ObjectIsNativeWrapper(aCx, obj)) {
    aRv.Throw(NS_ERROR_NOT_AVAILABLE);
    return JS::UndefinedValue();
  }

  obj = thisContent->GetWrapper();
  // Now wrap things up into the compartment of "obj"
  JSAutoCompartment ac(aCx, obj);
  JS::AutoValueVector args(aCx);
  if (!args.append(aArguments.Elements(), aArguments.Length())) {
    aRv.Throw(NS_ERROR_OUT_OF_MEMORY);
    return JS::UndefinedValue();
  }

  for (size_t i = 0; i < args.length(); i++) {
    if (!JS_WrapValue(aCx, args.handleAt(i))) {
      aRv.Throw(NS_ERROR_UNEXPECTED);
      return JS::UndefinedValue();
    }
  }

  JS::Rooted<JS::Value> thisVal(aCx, aThisVal);
  if (!JS_WrapValue(aCx, &thisVal)) {
    aRv.Throw(NS_ERROR_UNEXPECTED);
    return JS::UndefinedValue();
  }

  nsRefPtr<nsNPAPIPluginInstance> pi;
  nsresult rv = ScriptRequestPluginInstance(aCx, getter_AddRefs(pi));
  if (NS_FAILED(rv)) {
    aRv.Throw(rv);
    return JS::UndefinedValue();
  }

  // if there's no plugin around for this object, throw.
  if (!pi) {
    aRv.Throw(NS_ERROR_NOT_AVAILABLE);
    return JS::UndefinedValue();
  }

  JS::Rooted<JSObject*> pi_obj(aCx);
  JS::Rooted<JSObject*> pi_proto(aCx);

  rv = GetPluginJSObject(aCx, obj, pi, &pi_obj, &pi_proto);
  if (NS_FAILED(rv)) {
    aRv.Throw(rv);
    return JS::UndefinedValue();
  }

  if (!pi_obj) {
    aRv.Throw(NS_ERROR_NOT_AVAILABLE);
    return JS::UndefinedValue();
  }

  JS::Rooted<JS::Value> retval(aCx);
  bool ok = JS::Call(aCx, thisVal, pi_obj, args, &retval);
  if (!ok) {
    aRv.Throw(NS_ERROR_FAILURE);
    return JS::UndefinedValue();
  }

  Telemetry::Accumulate(Telemetry::PLUGIN_CALLED_DIRECTLY, true);
  return retval;
}

void
nsObjectLoadingContent::SetupProtoChain(JSContext* aCx,
                                        JS::Handle<JSObject*> aObject)
{
  MOZ_ASSERT(nsCOMPtr<nsIContent>(do_QueryInterface(
    static_cast<nsIObjectLoadingContent*>(this)))->IsDOMBinding());

  if (mType != eType_Plugin) {
    return;
  }

  if (!nsContentUtils::IsSafeToRunScript()) {
    // This may be null if the JS context is not a DOM context. That's ok, we'll
    // use the safe context from XPConnect in the runnable.
    nsCOMPtr<nsIScriptContext> scriptContext = GetScriptContextFromJSContext(aCx);

    nsRefPtr<SetupProtoChainRunner> runner =
      new SetupProtoChainRunner(scriptContext, this);
    nsContentUtils::AddScriptRunner(runner);
    return;
  }

  // We get called on random compartments here for some reason
  // (perhaps because WrapObject can happen on a random compartment?)
  // so make sure to enter the compartment of aObject.
  MOZ_ASSERT(aCx == nsContentUtils::GetCurrentJSContext());

  JSAutoCompartment ac(aCx, aObject);

  nsRefPtr<nsNPAPIPluginInstance> pi;
  nsresult rv = ScriptRequestPluginInstance(aCx, getter_AddRefs(pi));
  if (NS_FAILED(rv)) {
    return;
  }

  if (!pi) {
    // No plugin around for this object.
    return;
  }

  JS::Rooted<JSObject*> pi_obj(aCx); // XPConnect-wrapped peer object, when we get it.
  JS::Rooted<JSObject*> pi_proto(aCx); // 'pi.__proto__'

  rv = GetPluginJSObject(aCx, aObject, pi, &pi_obj, &pi_proto);
  if (NS_FAILED(rv)) {
    return;
  }

  if (!pi_obj) {
    // Didn't get a plugin instance JSObject, nothing we can do then.
    return;
  }

  // If we got an xpconnect-wrapped plugin object, set obj's
  // prototype's prototype to the scriptable plugin.

  JS::Rooted<JSObject*> global(aCx, JS_GetGlobalForObject(aCx, aObject));
  JS::Handle<JSObject*> my_proto = GetDOMClass(aObject)->mGetProto(aCx, global);
  MOZ_ASSERT(my_proto);

  // Set 'this.__proto__' to pi
  if (!::JS_SetPrototype(aCx, aObject, pi_obj)) {
    return;
  }

  if (pi_proto && js::GetObjectClass(pi_proto) != js::ObjectClassPtr) {
    // The plugin wrapper has a proto that's not Object.prototype, set
    // 'pi.__proto__.__proto__' to the original 'this.__proto__'
    if (pi_proto != my_proto && !::JS_SetPrototype(aCx, pi_proto, my_proto)) {
      return;
    }
  } else {
    // 'pi' didn't have a prototype, or pi's proto was
    // 'Object.prototype' (i.e. pi is an NPRuntime wrapped JS object)
    // set 'pi.__proto__' to the original 'this.__proto__'
    if (!::JS_SetPrototype(aCx, pi_obj, my_proto)) {
      return;
    }
  }

  // Before this proto dance the objects involved looked like this:
  //
  // this.__proto__.__proto__
  //   ^      ^         ^
  //   |      |         |__ Object.prototype
  //   |      |
  //   |      |__ WebIDL prototype (shared)
  //   |
  //   |__ WebIDL object
  //
  // pi.__proto__
  // ^      ^
  // |      |__ Object.prototype or some other object
  // |
  // |__ Plugin NPRuntime JS object wrapper
  //
  // Now, after the above prototype setup the prototype chain should
  // look like this if pi.__proto__ was Object.prototype:
  //
  // this.__proto__.__proto__.__proto__
  //   ^      ^         ^         ^
  //   |      |         |         |__ Object.prototype
  //   |      |         |
  //   |      |         |__ WebIDL prototype (shared)
  //   |      |
  //   |      |__ Plugin NPRuntime JS object wrapper
  //   |
  //   |__ WebIDL object
  //
  // or like this if pi.__proto__ was some other object:
  //
  // this.__proto__.__proto__.__proto__.__proto__
  //   ^      ^         ^         ^         ^
  //   |      |         |         |         |__ Object.prototype
  //   |      |         |         |
  //   |      |         |         |__ WebIDL prototype (shared)
  //   |      |         |
  //   |      |         |__ old pi.__proto__
  //   |      |
  //   |      |__ Plugin NPRuntime JS object wrapper
  //   |
  //   |__ WebIDL object
  //
}

// static
nsresult
nsObjectLoadingContent::GetPluginJSObject(JSContext *cx,
                                          JS::Handle<JSObject*> obj,
                                          nsNPAPIPluginInstance *plugin_inst,
                                          JS::MutableHandle<JSObject*> plugin_obj,
                                          JS::MutableHandle<JSObject*> plugin_proto)
{
  // NB: We need an AutoEnterCompartment because we can be called from
  // nsObjectFrame when the plugin loads after the JS object for our content
  // node has been created.
  JSAutoCompartment ac(cx, obj);

  if (plugin_inst) {
    plugin_inst->GetJSObject(cx, plugin_obj.address());
    if (plugin_obj) {
      if (!::JS_GetPrototype(cx, plugin_obj, plugin_proto)) {
        return NS_ERROR_UNEXPECTED;
      }
    }
  }

  return NS_OK;
}

void
nsObjectLoadingContent::TeardownProtoChain()
{
  nsCOMPtr<nsIContent> thisContent =
    do_QueryInterface(static_cast<nsIImageLoadingContent*>(this));

  // Use the safe JSContext here as we're not always able to find the
  // JSContext associated with the NPP any more.
  AutoSafeJSContext cx;
  JS::Rooted<JSObject*> obj(cx, thisContent->GetWrapper());
  NS_ENSURE_TRUE(obj, /* void */);

  JS::Rooted<JSObject*> proto(cx);
  JSAutoCompartment ac(cx, obj);

  // Loop over the DOM element's JS object prototype chain and remove
  // all JS objects of the class sNPObjectJSWrapperClass
  DebugOnly<bool> removed = false;
  while (obj) {
    if (!::JS_GetPrototype(cx, obj, &proto)) {
      return;
    }
    if (!proto) {
      break;
    }
    // Unwrap while checking the jsclass - if the prototype is a wrapper for
    // an NP object, that counts too.
    if (JS_GetClass(js::UncheckedUnwrap(proto)) == &sNPObjectJSWrapperClass) {
      // We found an NPObject on the proto chain, get its prototype...
      if (!::JS_GetPrototype(cx, proto, &proto)) {
        return;
      }

      MOZ_ASSERT(!removed, "more than one NPObject in prototype chain");
      removed = true;

      // ... and pull it out of the chain.
      ::JS_SetPrototype(cx, obj, proto);
    }

    obj = proto;
  }
}

bool
nsObjectLoadingContent::DoNewResolve(JSContext* aCx, JS::Handle<JSObject*> aObject,
                                     JS::Handle<jsid> aId,
                                     JS::MutableHandle<JSPropertyDescriptor> aDesc)
{
  // We don't resolve anything; we just try to make sure we're instantiated.
  // This purposefully does not fire for chrome/xray resolves, see bug 967694

  nsRefPtr<nsNPAPIPluginInstance> pi;
  nsresult rv = ScriptRequestPluginInstance(aCx, getter_AddRefs(pi));
  if (NS_FAILED(rv)) {
    return mozilla::dom::Throw(aCx, rv);
  }
  return true;
}

void
nsObjectLoadingContent::GetOwnPropertyNames(JSContext* aCx,
                                            nsTArray<nsString>& /* unused */,
                                            ErrorResult& aRv)
{
  // Just like DoNewResolve, just make sure we're instantiated.  That will do
  // the work our Enumerate hook needs to do.  This purposefully does not fire
  // for xray resolves, see bug 967694
  nsRefPtr<nsNPAPIPluginInstance> pi;
  aRv = ScriptRequestPluginInstance(aCx, getter_AddRefs(pi));
}


// SetupProtoChainRunner implementation
nsObjectLoadingContent::SetupProtoChainRunner::SetupProtoChainRunner(
    nsIScriptContext* scriptContext,
    nsObjectLoadingContent* aContent)
  : mContext(scriptContext)
  , mContent(aContent)
{
}

NS_IMETHODIMP
nsObjectLoadingContent::SetupProtoChainRunner::Run()
{
  // XXXbz Does it really matter what JSContext we use here?  Seems
  // like we could just always use the safe context....
  nsCxPusher pusher;
  JSContext* cx = mContext ? mContext->GetNativeContext()
                           : nsContentUtils::GetSafeJSContext();
  pusher.Push(cx);

  nsCOMPtr<nsIContent> content;
  CallQueryInterface(mContent.get(), getter_AddRefs(content));
  JS::Rooted<JSObject*> obj(cx, content->GetWrapper());
  if (!obj) {
    // No need to set up our proto chain if we don't even have an object
    return NS_OK;
  }
  nsObjectLoadingContent* objectLoadingContent =
    static_cast<nsObjectLoadingContent*>(mContent.get());
  objectLoadingContent->SetupProtoChain(cx, obj);
  return NS_OK;
}

NS_IMPL_ISUPPORTS1(nsObjectLoadingContent::SetupProtoChainRunner, nsIRunnable)