--- a/dom/base/nsObjectLoadingContent.cpp
+++ b/dom/base/nsObjectLoadingContent.cpp
@@ -83,32 +83,26 @@
 #include "mozilla/dom/ScriptSettings.h"
 #include "mozilla/dom/PluginCrashedEvent.h"
 #include "mozilla/AsyncEventDispatcher.h"
 #include "mozilla/EventDispatcher.h"
 #include "mozilla/EventStates.h"
 #include "mozilla/Telemetry.h"
 #include "mozilla/dom/HTMLObjectElementBinding.h"
 #include "mozilla/dom/HTMLSharedObjectElement.h"
+#include "mozilla/dom/HTMLObjectElement.h"
 #include "nsChannelClassifier.h"
 
 #ifdef XP_WIN
 // Thanks so much, Microsoft! :(
 #ifdef CreateEvent
 #undef CreateEvent
 #endif
 #endif // XP_WIN
 
-#ifdef XP_MACOSX
-// HandlePluginCrashed() and HandlePluginInstantiated() needed from here to
-// fix bug 1147521.  Should later be replaced by proper interface methods,
-// maybe on nsIObjectLoadingContext.
-#include "mozilla/dom/HTMLObjectElement.h"
-#endif
-
 static NS_DEFINE_CID(kAppShellCID, NS_APPSHELL_CID);
 
 static const char *kPrefJavaMIME = "plugin.java.mime";
 static const char *kPrefYoutubeRewrite = "plugins.rewrite_youtube_embeds";
 static const char *kPrefBlockURIs = "browser.safebrowsing.blockedURIs.enabled";
 static const char *kPrefFavorFallbackMode = "plugins.favorfallback.mode";
 static const char *kPrefFavorFallbackRules = "plugins.favorfallback.rules";
 
@@ -3013,50 +3007,53 @@ nsObjectLoadingContent::LoadFallback(Fal
 
   NS_ASSERTION(!mInstanceOwner && !mFrameLoader && !mChannel,
                "LoadFallback called with loaded content");
 
   //
   // Fixup mFallbackType
   //
   nsCOMPtr<nsIContent> thisContent =
-  do_QueryInterface(static_cast<nsIImageLoadingContent*>(this));
+    do_QueryInterface(static_cast<nsIImageLoadingContent*>(this));
   NS_ASSERTION(thisContent, "must be a content");
 
   if (!thisContent->IsHTMLElement() || mContentType.IsEmpty()) {
     // Don't let custom fallback handlers run outside HTML, tags without a
     // determined type should always just be alternate content
     aType = eFallbackAlternate;
   }
 
   // We'll set this to null no matter what now, doing it here means we'll load
   // child embeds as we find them in the upcoming loop.
   mType = eType_Null;
 
-  // Do a breadth-first traverse of node tree with the current element as root,
-  // looking for the first embed we can find.
+  bool thisIsObject = thisContent->IsHTMLElement(nsGkAtoms::object);
+
+  // Do a depth-first traverse of node tree with the current element as root,
+  // looking for <embed> or <object> elements that might now need to load.
   nsTArray<nsINodeList*> childNodes;
   if ((thisContent->IsHTMLElement(nsGkAtoms::object) ||
        thisContent->IsHTMLElement(nsGkAtoms::applet)) &&
       (aType == eFallbackUnsupported ||
        aType == eFallbackDisabled ||
        aType == eFallbackBlocklisted ||
        aType == eFallbackAlternate))
   {
     for (nsIContent* child = thisContent->GetFirstChild(); child;
          child = child->GetNextNode(thisContent)) {
       if (aType != eFallbackAlternate &&
           !child->IsHTMLElement(nsGkAtoms::param) &&
           nsStyleUtil::IsSignificantChild(child, true, false)) {
         aType = eFallbackAlternate;
       }
-      if (child->IsHTMLElement(nsGkAtoms::embed) &&
-          thisContent->IsHTMLElement(nsGkAtoms::object)) {
-        HTMLSharedObjectElement* object = static_cast<HTMLSharedObjectElement*>(child);
-        if (object) {
+      if (thisIsObject) {
+        if (child->IsHTMLElement(nsGkAtoms::embed)) {
+          HTMLSharedObjectElement* embed = static_cast<HTMLSharedObjectElement*>(child);
+          embed->StartObjectLoad(true, true);
+        } else if (auto object = HTMLObjectElement::FromContent(child)) {
           object->StartObjectLoad(true, true);
         }
       }
     }
   }
 
   mFallbackType = aType;
 
@@ -3812,16 +3809,48 @@ nsObjectLoadingContent::MaybeFireErrorEv
     RefPtr<AsyncEventDispatcher> loadBlockingAsyncDispatcher =
       new LoadBlockingAsyncEventDispatcher(thisContent,
                                            NS_LITERAL_STRING("error"),
                                            false, false);
     loadBlockingAsyncDispatcher->PostDOMEvent();
   }
 }
 
+bool
+nsObjectLoadingContent::BlockEmbedOrObjectContentLoading()
+{
+  nsCOMPtr<nsIContent> thisContent =
+    do_QueryInterface(static_cast<nsIImageLoadingContent*>(this));
+  if (!thisContent->IsHTMLElement(nsGkAtoms::embed) &&
+      !thisContent->IsHTMLElement(nsGkAtoms::object)) {
+    // Doesn't apply to other elements (i.e. <applet>)
+    return false;
+  }
+
+  // Traverse up the node tree to see if we have any ancestors that may block us
+  // from loading
+  for (nsIContent* parent = thisContent->GetParent();
+       parent;
+       parent = parent->GetParent()) {
+    if (parent->IsAnyOfHTMLElements(nsGkAtoms::video, nsGkAtoms::audio)) {
+      return true;
+    }
+    // If we have an ancestor that is an object with a source, it'll have an
+    // associated displayed type. If that type is not null, don't load content
+    // for the embed.
+    if (HTMLObjectElement* object = HTMLObjectElement::FromContent(parent)) {
+      uint32_t type = object->DisplayedType();
+      if (type != eType_Null) {
+        return true;
+      }
+    }
+  }
+  return false;
+}
+
 // SetupProtoChainRunner implementation
 nsObjectLoadingContent::SetupProtoChainRunner::SetupProtoChainRunner(
     nsObjectLoadingContent* aContent)
   : mContent(aContent)
 {
 }
 
 NS_IMETHODIMP

--- a/dom/base/nsObjectLoadingContent.h
+++ b/dom/base/nsObjectLoadingContent.h
@@ -329,16 +329,31 @@ class nsObjectLoadingContent : public ns
     void UnbindFromTree(bool aDeep = true,
                         bool aNullParent = true);
 
     /**
      * Return the content policy type used for loading the element.
      */
     virtual nsContentPolicyType GetContentPolicyType() const = 0;
 
+    /**
+     * Decides whether we should load <embed>/<object> node content.
+     *
+     * If this is an <embed> or <object> node there are cases in which we should
+     * not try to load the content:
+     *
+     * - If the node is the child of a media element
+     * - If the node is the child of an <object> node that already has
+     *   content being loaded.
+     *
+     * In these cases, this function will return false, which will cause
+     * us to skip calling LoadObject.
+     */
+    bool BlockEmbedOrObjectContentLoading();
+
   private:
 
     // Object parameter changes returned by UpdateObjectParameters
     enum ParameterUpdateFlags {
       eParamNoChange           = 0,
       // Parameters that potentially affect the channel changed
       // - mOriginalURI, mOriginalContentType
       eParamChannelChanged     = 1u << 0,

--- a/dom/html/HTMLObjectElement.cpp
+++ b/dom/html/HTMLObjectElement.cpp
@@ -74,17 +74,17 @@ HTMLObjectElement::IsDoneAddingChildren(
 void
 HTMLObjectElement::DoneAddingChildren(bool aHaveNotified)
 {
   mIsDoneAddingChildren = true;
 
   // If we're already in a document, we need to trigger the load
   // Otherwise, BindToTree takes care of that.
   if (IsInComposedDoc()) {
-    StartObjectLoad(aHaveNotified);
+    StartObjectLoad(aHaveNotified, false);
   }
 }
 
 NS_IMPL_CYCLE_COLLECTION_CLASS(HTMLObjectElement)
 
 NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN_INHERITED(HTMLObjectElement,
                                                   nsGenericHTMLFormElement)
   NS_IMPL_CYCLE_COLLECTION_TRAVERSE(mValidity)
@@ -305,34 +305,36 @@ HTMLObjectElement::SetAttr(int32_t aName
   // if aNotify is false, we are coming from the parser or some such place;
   // we'll get bound after all the attributes have been set, so we'll do the
   // object load from BindToTree/DoneAddingChildren.
   // Skip the LoadObject call in that case.
   // We also don't want to start loading the object when we're not yet in
   // a document, just in case that the caller wants to set additional
   // attributes before inserting the node into the document.
   if (aNotify && IsInComposedDoc() && mIsDoneAddingChildren &&
-      aNameSpaceID == kNameSpaceID_None && aName == nsGkAtoms::data) {
+      aNameSpaceID == kNameSpaceID_None && aName == nsGkAtoms::data &&
+      !BlockEmbedOrObjectContentLoading()) {
     return LoadObject(aNotify, true);
   }
 
   return NS_OK;
 }
 
 nsresult
 HTMLObjectElement::UnsetAttr(int32_t aNameSpaceID, nsIAtom* aAttribute,
                              bool aNotify)
 {
   nsresult rv = nsGenericHTMLFormElement::UnsetAttr(aNameSpaceID,
                                                     aAttribute, aNotify);
   NS_ENSURE_SUCCESS(rv, rv);
 
   // See comment in SetAttr
   if (aNotify && IsInComposedDoc() && mIsDoneAddingChildren &&
-      aNameSpaceID == kNameSpaceID_None && aAttribute == nsGkAtoms::data) {
+      aNameSpaceID == kNameSpaceID_None && aAttribute == nsGkAtoms::data &&
+      !BlockEmbedOrObjectContentLoading()) {
     return LoadObject(aNotify, true);
   }
 
   return NS_OK;
 }
 
 bool
 HTMLObjectElement::IsFocusableForTabIndex()
@@ -530,25 +532,26 @@ HTMLObjectElement::IsAttributeMapped(con
 
 nsMapRuleToAttributesFunc
 HTMLObjectElement::GetAttributeMappingFunction() const
 {
   return &MapAttributesIntoRule;
 }
 
 void
-HTMLObjectElement::StartObjectLoad(bool aNotify)
+HTMLObjectElement::StartObjectLoad(bool aNotify, bool aForce)
 {
   // BindToTree can call us asynchronously, and we may be removed from the tree
   // in the interim
-  if (!IsInComposedDoc() || !OwnerDoc()->IsActive()) {
+  if (!IsInComposedDoc() || !OwnerDoc()->IsActive() ||
+      BlockEmbedOrObjectContentLoading()) {
     return;
   }
 
-  LoadObject(aNotify);
+  LoadObject(aNotify, aForce);
   SetIsNetworkCreated(false);
 }
 
 EventStates
 HTMLObjectElement::IntrinsicState() const
 {
   return nsGenericHTMLFormElement::IntrinsicState() | ObjectState();
 }

--- a/dom/html/HTMLObjectElement.h
+++ b/dom/html/HTMLObjectElement.h
@@ -93,17 +93,17 @@ public:
 
   // nsObjectLoadingContent
   virtual uint32_t GetCapabilities() const override;
 
   virtual nsresult Clone(mozilla::dom::NodeInfo *aNodeInfo, nsINode **aResult) const override;
 
   nsresult CopyInnerTo(Element* aDest);
 
-  void StartObjectLoad() { StartObjectLoad(true); }
+  void StartObjectLoad() { StartObjectLoad(true, false); }
 
   NS_DECL_CYCLE_COLLECTION_CLASS_INHERITED(HTMLObjectElement,
                                            nsGenericHTMLFormElement)
 
   // Web IDL binding methods
   // XPCOM GetData is ok; note that it's a URI attribute with a weird base URI
   void SetData(const nsAString& aValue, ErrorResult& aRv)
   {
@@ -242,22 +242,22 @@ public:
   }
 
   nsIDocument*
   GetSVGDocument(nsIPrincipal& aSubjectPrincipal)
   {
     return GetContentDocument(aSubjectPrincipal);
   }
 
-private:
   /**
    * Calls LoadObject with the correct arguments to start the plugin load.
    */
-  void StartObjectLoad(bool aNotify);
+  void StartObjectLoad(bool aNotify, bool aForceLoad);
 
+private:
   /**
    * Returns if the element is currently focusable regardless of it's tabindex
    * value. This is used to know the default tabindex value.
    */
   bool IsFocusableForTabIndex();
 
   nsContentPolicyType GetContentPolicyType() const override
   {

--- a/dom/html/HTMLSharedObjectElement.cpp
+++ b/dom/html/HTMLSharedObjectElement.cpp
@@ -175,17 +175,17 @@ HTMLSharedObjectElement::SetAttr(int32_t
   // we'll get bound after all the attributes have been set, so we'll do the
   // object load from BindToTree/DoneAddingChildren.
   // Skip the LoadObject call in that case.
   // We also don't want to start loading the object when we're not yet in
   // a document, just in case that the caller wants to set additional
   // attributes before inserting the node into the document.
   if (aNotify && IsInComposedDoc() && mIsDoneAddingChildren &&
       aNameSpaceID == kNameSpaceID_None && aName == URIAttrName()
-      && !BlockEmbedContentLoading()) {
+      && !BlockEmbedOrObjectContentLoading()) {
     return LoadObject(aNotify, true);
   }
 
   return NS_OK;
 }
 
 bool
 HTMLSharedObjectElement::IsHTMLFocusable(bool aWithMouse,
@@ -308,17 +308,17 @@ HTMLSharedObjectElement::GetAttributeMap
 }
 
 void
 HTMLSharedObjectElement::StartObjectLoad(bool aNotify, bool aForceLoad)
 {
   // BindToTree can call us asynchronously, and we may be removed from the tree
   // in the interim
   if (!IsInComposedDoc() || !OwnerDoc()->IsActive() ||
-      BlockEmbedContentLoading()) {
+      BlockEmbedOrObjectContentLoading()) {
     return;
   }
 
   LoadObject(aNotify, aForceLoad);
   SetIsNetworkCreated(false);
 }
 
 EventStates
@@ -384,36 +384,10 @@ HTMLSharedObjectElement::GetContentPolic
     // through RequestContext yet.
     return nsIContentPolicy::TYPE_INTERNAL_OBJECT;
   } else {
     MOZ_ASSERT(mNodeInfo->Equals(nsGkAtoms::embed));
     return nsIContentPolicy::TYPE_INTERNAL_EMBED;
   }
 }
 
-bool
-HTMLSharedObjectElement::BlockEmbedContentLoading()
-{
-  // Only check on embed elements
-  if (!IsHTMLElement(nsGkAtoms::embed)) {
-    return false;
-  }
-  // Traverse up the node tree to see if we have any ancestors that may block us
-  // from loading
-  for (nsIContent* parent = GetParent(); parent; parent = parent->GetParent()) {
-    if (parent->IsAnyOfHTMLElements(nsGkAtoms::video, nsGkAtoms::audio)) {
-      return true;
-    }
-    // If we have an ancestor that is an object with a source, it'll have an
-    // associated displayed type. If that type is not null, don't load content
-    // for the embed.
-    if (HTMLObjectElement* object = HTMLObjectElement::FromContent(parent)) {
-      uint32_t type = object->DisplayedType();
-      if (type != eType_Null) {
-        return true;
-      }
-    }
-  }
-  return false;
-}
-
 } // namespace dom
 } // namespace mozilla

--- a/dom/html/HTMLSharedObjectElement.h
+++ b/dom/html/HTMLSharedObjectElement.h
@@ -215,29 +215,14 @@ private:
   // mIsDoneAddingChildren is only really used for <applet>.  This boolean is
   // always true for <embed>, per the documentation in nsIContent.h.
   bool mIsDoneAddingChildren;
 
   virtual JSObject* WrapNode(JSContext *aCx, JS::Handle<JSObject*> aGivenProto) override;
 
   static void MapAttributesIntoRule(const nsMappedAttributes* aAttributes,
                                     GenericSpecifiedValues* aGenericData);
-
-  /**
-   * Decides whether we should load embed node content.
-   *
-   * If this is an embed node there are cases in which we should not try to load
-   * the content:
-   *
-   * - If the embed node is the child of a media element
-   * - If the embed node is the child of an object node that already has
-   *   content being loaded.
-   *
-   * In these cases, this function will return false, which will cause
-   * us to skip calling LoadObject.
-   */
-  bool BlockEmbedContentLoading();
 };
 
 } // namespace dom
 } // namespace mozilla
 
 #endif // mozilla_dom_HTMLSharedObjectElement_h

--- a/dom/tests/mochitest/general/resource_timing_cross_origin.html
+++ b/dom/tests/mochitest/general/resource_timing_cross_origin.html
@@ -165,23 +165,23 @@ function finishTests() {
 <body>
   <a target="_blank"
      href="https://bugzilla.mozilla.org/show_bug.cgi?id=822480"
      title="Add resource timing API.">
     Bug #822480 -  Add in the Resource Timing API
   </a>
   <p id="display"></p>
   <div id="content">
-    <object data="http://mochi.test:8888/tests/dom/tests/mochitest/general/res0.resource"> <!-- same origin, no header -->
-    <object data="http://test1.example.com/tests/dom/tests/mochitest/general/res0.resource"> <!-- cross origin, no header -->
-    <object data="http://test1.example.com/tests/dom/tests/mochitest/general/res1.resource"> <!-- cross origin, Timing-Allow-Origin: * header -->
-    <object data="http://test1.example.com/tests/dom/tests/mochitest/general/res2.resource"> <!-- cross origin redirect to test2.example.com, no header -->
-    <object data="http://test1.example.com/tests/dom/tests/mochitest/general/res3.resource"> <!-- cross origin, Timing-Allow-Origin: http://mochi.test:8888 header -->
-    <object data="http://test1.example.com/tests/dom/tests/mochitest/general/res4.resource"> <!-- cross origin redirect to mochi.test:8888/.../res1.resource, Timing-Allow-Origin: * -->
-    <object data="http://test1.example.com/tests/dom/tests/mochitest/general/res5.resource"> <!-- cross origin, Timing-Allow-Origin: http://mochi.test:8889 -->
-    <object data="http://test1.example.com/tests/dom/tests/mochitest/general/res6.resource"> <!-- cross origin, Timing-Allow-Origin: "" (empty string) -->
-    <object data="http://test1.example.com/tests/dom/tests/mochitest/general/res7.resource"> <!-- cross origin, Timing-Allow-Origin: http://mochi.test:8888 http://test1.com header -->
-    <object data="http://test1.example.com/tests/dom/tests/mochitest/general/res8.resource"> <!-- double cross origin redirect -->
+    <object data="http://mochi.test:8888/tests/dom/tests/mochitest/general/res0.resource"></object> <!-- same origin, no header -->
+    <object data="http://test1.example.com/tests/dom/tests/mochitest/general/res0.resource"></object> <!-- cross origin, no header -->
+    <object data="http://test1.example.com/tests/dom/tests/mochitest/general/res1.resource"></object> <!-- cross origin, Timing-Allow-Origin: * header -->
+    <object data="http://test1.example.com/tests/dom/tests/mochitest/general/res2.resource"></object> <!-- cross origin redirect to test2.example.com, no header -->
+    <object data="http://test1.example.com/tests/dom/tests/mochitest/general/res3.resource"></object> <!-- cross origin, Timing-Allow-Origin: http://mochi.test:8888 header -->
+    <object data="http://test1.example.com/tests/dom/tests/mochitest/general/res4.resource"></object> <!-- cross origin redirect to mochi.test:8888/.../res1.resource, Timing-Allow-Origin: * -->
+    <object data="http://test1.example.com/tests/dom/tests/mochitest/general/res5.resource"></object> <!-- cross origin, Timing-Allow-Origin: http://mochi.test:8889 -->
+    <object data="http://test1.example.com/tests/dom/tests/mochitest/general/res6.resource"></object> <!-- cross origin, Timing-Allow-Origin: "" (empty string) -->
+    <object data="http://test1.example.com/tests/dom/tests/mochitest/general/res7.resource"></object> <!-- cross origin, Timing-Allow-Origin: http://mochi.test:8888 http://test1.com header -->
+    <object data="http://test1.example.com/tests/dom/tests/mochitest/general/res8.resource"></object> <!-- double cross origin redirect -->
     <script type="text/javascript" src="http://mochi.test:8888/tests/dom/tests/mochitest/general/resource_timing.js"></script> <!-- same origin script -->
   </div>
 </body>
 
 </html>

--- a/testing/web-platform/meta/MANIFEST.json
+++ b/testing/web-platform/meta/MANIFEST.json
@@ -92462,16 +92462,28 @@
     ]
    ],
    "html/semantics/embedded-content/the-object-element/object-handler.html": [
     [
      "/html/semantics/embedded-content/the-object-element/object-handler.html",
      {}
     ]
    ],
+   "html/semantics/embedded-content/the-object-element/object-ignored-in-media-element.html": [
+    [
+     "/html/semantics/embedded-content/the-object-element/object-ignored-in-media-element.html",
+     {}
+    ]
+   ],
+   "html/semantics/embedded-content/the-object-element/object-in-object-fallback-2.html": [
+    [
+     "/html/semantics/embedded-content/the-object-element/object-in-object-fallback-2.html",
+     {}
+    ]
+   ],
    "html/semantics/embedded-content/the-object-element/usemap-casing.html": [
     [
      "/html/semantics/embedded-content/the-object-element/usemap-casing.html",
      {}
     ]
    ],
    "html/semantics/embedded-content/the-video-element/video-tabindex.html": [
     [
@@ -174544,17 +174556,17 @@
    "e6611c20a50884639a51010836bb2b1bdfb9cab8",
    "testharness"
   ],
   "html/semantics/embedded-content/the-embed-element/embed-iframe.html": [
    "96a043e993bccf1896f5a19960a1bff5dce0e79d",
    "support"
   ],
   "html/semantics/embedded-content/the-embed-element/embed-ignored-in-media-element.html": [
-   "94a08a7a5b5ec5c26f1974d5e5d8b4381a60baf5",
+   "cb57cbe52e4f586006461b8eae6bc233b5ed5ad5",
    "testharness"
   ],
   "html/semantics/embedded-content/the-embed-element/embed-in-object-fallback-2.html": [
    "a7da1fefb2403084205bf1ead77b422e69dc33b6",
    "testharness"
   ],
   "html/semantics/embedded-content/the-embed-element/embed-in-object-fallback-subdocument.html": [
    "1b60c4e5c8868fe87553b78047e711d63702a673",
@@ -174867,16 +174879,24 @@
   "html/semantics/embedded-content/the-object-element/object-fallback.html": [
    "7bb46b36376a1afd004cf0537bdedd975088b2f2",
    "testharness"
   ],
   "html/semantics/embedded-content/the-object-element/object-handler.html": [
    "bf051d12a045698b2f9c3870ad4236f65bb85f51",
    "testharness"
   ],
+  "html/semantics/embedded-content/the-object-element/object-ignored-in-media-element.html": [
+   "62a6c079bc00ae6ebeca363fd42d8701c4791222",
+   "testharness"
+  ],
+  "html/semantics/embedded-content/the-object-element/object-in-object-fallback-2.html": [
+   "a5bb885111ac7ea02241957ee7233491c2277516",
+   "testharness"
+  ],
   "html/semantics/embedded-content/the-object-element/test0.html": [
    "04319dea2f1e0b00e8db1703f2072ec22f1a82ad",
    "support"
   ],
   "html/semantics/embedded-content/the-object-element/test1.html": [
    "c083a73f9b0f3d2f4a3796f113144227e6567d0f",
    "support"
   ],

copy from testing/web-platform/tests/html/semantics/embedded-content/the-embed-element/embed-ignored-in-media-element.html
copy to testing/web-platform/tests/html/semantics/embedded-content/the-object-element/object-ignored-in-media-element.html
--- a/testing/web-platform/tests/html/semantics/embedded-content/the-embed-element/embed-ignored-in-media-element.html
+++ b/testing/web-platform/tests/html/semantics/embedded-content/the-object-element/object-ignored-in-media-element.html
@@ -1,22 +1,22 @@
 <!doctype html>
 <meta charset="utf-8">
 <title>HTML Test: The embed element represents a document</title>
 <script src="/resources/testharness.js"></script>
 <script src="/resources/testharnessreport.js"></script>
-<meta name="assert" content="Check if the embed element is ignored when used inside a media element">
+<meta name="assert" content="Check if the object element is ignored when used inside a media element">
 <script type="application/javascript">
-  var nestingTest = async_test("Test embed being ignored inside media element");
+  var nestingTest = async_test("Test <object> being ignored inside media element");
   onload = nestingTest.step_func_done(function() {
     assert_true(true, "We got to a load event without loading things we should not load");
   });
 </script>
 <body>
   <video>
-    <embed type="text/html" src="../resources/should-not-load.html"
-           test-description="<embed> in <video>">
+    <object type="text/html" data="../resources/should-not-load.html"
+            test-description="<object> in <video>"></object>
   </video>
   <audio>
-    <embed type="text/html" src="../resources/should-not-load.html"
-           test-description="<embed> in <audio>">
+    <object type="text/html" data="../resources/should-not-load.html"
+            test-description="<object> in <audio>"></object>
   </audio>
 </body>

copy from testing/web-platform/tests/html/semantics/embedded-content/the-embed-element/embed-in-object-fallback-2.html
copy to testing/web-platform/tests/html/semantics/embedded-content/the-object-element/object-in-object-fallback-2.html
--- a/testing/web-platform/tests/html/semantics/embedded-content/the-embed-element/embed-in-object-fallback-2.html
+++ b/testing/web-platform/tests/html/semantics/embedded-content/the-object-element/object-in-object-fallback-2.html
@@ -2,55 +2,55 @@
 <html>
   <head>
     <meta charset=utf-8>
     <title></title>
     <script src=/resources/testharness.js></script>
     <script src=/resources/testharnessreport.js></script>
     <script>
       var loadedCount = 0;
-      var nestingTest = async_test("Test <embed> nesting inside <object>");
+      var nestingTest = async_test("Test <object> nesting inside <object>");
       onload = nestingTest.step_func_done(function() {
         assert_equals(loadedCount, 12, "Should have loaded all should-load elements");
       });
     </script>
     <style>
-      object, embed { display: none }
+      object { display: none }
     </style>
   </head>
   <body>
     <object data="../resources/should-load.html" style="width: 100px; height: 100px">
-      <embed type="text/html" src="../resources/should-not-load.html"
-             test-description="<embed> inside <object>">
+      <object type="text/html" data="../resources/should-not-load.html"
+              test-description="<object> inside <object>"></object>
     </object>
     <object style="width: 100px; height: 100px" data="data:application/x-does-not-exist,test">
-      <embed type="text/html" src="../resources/should-load.html" />
+      <object type="text/html" data="../resources/should-load.html"></object>
     </object>
     <object style="width: 100px; height: 100px" data="data:application/x-does-not-exist,test">
       <div></div>
-      <embed type="text/html" src="../resources/should-load.html" />
+      <object type="text/html" data="../resources/should-load.html"></object>
     </object>
     <object style="width: 100px; height: 100px" data="data:application/x-does-not-exist,test">
       <div>
-        <embed type="text/html" src="../resources/should-load.html" />
+        <object type="text/html" data="../resources/should-load.html"></object>
       </div>
     </object>
     <object style="width: 100px; height: 100px" data="data:application/x-does-not-exist,test">
-      <embed type="text/html" src="../resources/should-load.html" />
-      <embed type="text/html" src="../resources/should-load.html" />
+      <object type="text/html" data="../resources/should-load.html"></object>
+      <object type="text/html" data="../resources/should-load.html"></object>
       <object data="../resources/should-load.html">
-        <embed type="text/html" src="../resources/should-not-load.html"
-               test-description="<embed> inside loaded <object> inside non-loaded <object>">
+        <object type="text/html" data="../resources/should-not-load.html"
+                test-description="<object> inside loaded <object> inside non-loaded <object>"></object>
       </object>
       <object data="data:application/x-does-not-exist,test">
-        <embed type="text/html" src="../resources/should-load.html" />
+        <object type="text/html" data="../resources/should-load.html"></object>
       </object>
     </object>
     <div>
       <object data="../resources/should-load.html" style="width: 100px; height: 100px"></object>
-      <embed type="text/html" src="../resources/should-load.html" />
+      <object type="text/html" data="../resources/should-load.html"></object>
     </div>
     <div>
-      <embed type="text/html" src="../resources/should-load.html" />
+      <object type="text/html" data="../resources/should-load.html"></object>
       <object data="../resources/should-load.html" style="width: 100px; height: 100px"></object>
     </div>
   </body>
 </html>