--- a/content/base/public/nsContentTypeParser.h
+++ b/content/base/public/nsContentTypeParser.h
@@ -7,17 +7,17 @@
 #define nsContentTypeParser_h
 
 #include "nsAString.h"
 
 class nsIMIMEHeaderParam;
 
 class nsContentTypeParser {
 public:
-  nsContentTypeParser(const nsAString& aString);
+  explicit nsContentTypeParser(const nsAString& aString);
   ~nsContentTypeParser();
 
   nsresult GetParameter(const char* aParameterName, nsAString& aResult);
   nsresult GetType(nsAString& aResult)
   {
     return GetParameter(nullptr, aResult);
   }
 

--- a/content/base/public/nsDocElementCreatedNotificationRunner.h
+++ b/content/base/public/nsDocElementCreatedNotificationRunner.h
@@ -11,17 +11,17 @@
 
 #include "nsContentSink.h"
 #include "nsCOMPtr.h"
 #include "nsIDocument.h"
 
 class nsDocElementCreatedNotificationRunner : public nsRunnable
 {
 public:
-  nsDocElementCreatedNotificationRunner(nsIDocument* aDoc)
+  explicit nsDocElementCreatedNotificationRunner(nsIDocument* aDoc)
     : mDoc(aDoc)
   {
   }
 
   NS_IMETHOD Run() MOZ_OVERRIDE
   {
     nsContentSink::NotifyDocElementCreated(mDoc);
     return NS_OK;

--- a/content/base/public/nsIScriptElement.h
+++ b/content/base/public/nsIScriptElement.h
@@ -22,17 +22,17 @@
 
 /**
  * Internal interface implemented by script elements
  */
 class nsIScriptElement : public nsIScriptLoaderObserver {
 public:
   NS_DECLARE_STATIC_IID_ACCESSOR(NS_ISCRIPTELEMENT_IID)
 
-  nsIScriptElement(mozilla::dom::FromParser aFromParser)
+  explicit nsIScriptElement(mozilla::dom::FromParser aFromParser)
     : mLineNumber(0),
       mAlreadyStarted(false),
       mMalformed(false),
       mDoneAddingChildren(aFromParser == mozilla::dom::NOT_FROM_PARSER ||
                           aFromParser == mozilla::dom::FROM_PARSER_FRAGMENT),
       mForceAsync(aFromParser == mozilla::dom::NOT_FROM_PARSER ||
                   aFromParser == mozilla::dom::FROM_PARSER_FRAGMENT),
       mFrozen(false),

--- a/content/base/public/nsTreeSanitizer.h
+++ b/content/base/public/nsTreeSanitizer.h
@@ -19,17 +19,17 @@ class MOZ_STACK_CLASS nsTreeSanitizer {
 
   public:
 
     /**
      * The constructor.
      *
      * @param aFlags Flags from nsIParserUtils
      */
-    nsTreeSanitizer(uint32_t aFlags = 0);
+    explicit nsTreeSanitizer(uint32_t aFlags = 0);
 
     static void InitializeStatics();
     static void ReleaseStatics();
 
     /**
      * Sanitizes a disconnected DOM fragment freshly obtained from a parser.
      * The argument must be of type nsINode::eDOCUMENT_FRAGMENT and,
      * consequently, must not be in the document. Furthermore, the fragment

--- a/content/base/public/nsXMLNameSpaceMap.h
+++ b/content/base/public/nsXMLNameSpaceMap.h
@@ -8,17 +8,17 @@
 
 #include "nsString.h"
 #include "nsTArray.h"
 #include "nsCOMPtr.h"
 #include "nsIAtom.h"
 
 struct nsNameSpaceEntry
 {
-  nsNameSpaceEntry(nsIAtom *aPrefix)
+  explicit nsNameSpaceEntry(nsIAtom* aPrefix)
     : prefix(aPrefix) {}
 
   nsCOMPtr<nsIAtom> prefix;
   int32_t nameSpaceID;
 };
 
 /**
  * nsXMLNameSpaceMap contains a set of prefixes which are mapped onto

--- a/content/base/src/ChildIterator.cpp
+++ b/content/base/src/ChildIterator.cpp
@@ -13,20 +13,20 @@
 #include "nsIAnonymousContentCreator.h"
 #include "nsIFrame.h"
 
 namespace mozilla {
 namespace dom {
 
 class MatchedNodes {
 public:
-  MatchedNodes(HTMLContentElement* aInsertionPoint)
+  explicit MatchedNodes(HTMLContentElement* aInsertionPoint)
     : mIsContentElement(true), mContentElement(aInsertionPoint) {}
 
-  MatchedNodes(XBLChildrenElement* aInsertionPoint)
+  explicit MatchedNodes(XBLChildrenElement* aInsertionPoint)
     : mIsContentElement(false), mChildrenElement(aInsertionPoint) {}
 
   uint32_t Length() const
   {
     return mIsContentElement ? mContentElement->MatchedNodes().Length()
                              : mChildrenElement->InsertedChildrenLength();
   }
 

--- a/content/base/src/ChildIterator.h
+++ b/content/base/src/ChildIterator.h
@@ -30,17 +30,17 @@ namespace dom {
 // <xbl:children> nodes replaced by the elements that have been filtered into that
 // insertion point. Any bindings on the given element are ignored for purposes
 // of determining which insertion point children are filtered into. The iterator
 // can be initialized to start at the end by providing false for aStartAtBeginning
 // in order to start iterating in reverse from the last child.
 class ExplicitChildIterator
 {
 public:
-  ExplicitChildIterator(nsIContent* aParent, bool aStartAtBeginning = true)
+  explicit ExplicitChildIterator(nsIContent* aParent, bool aStartAtBeginning = true)
     : mParent(aParent),
       mChild(nullptr),
       mDefaultChild(nullptr),
       mIndexInInserted(0),
       mIsFirst(aStartAtBeginning)
   {
   }
 
@@ -121,17 +121,17 @@ protected:
 };
 
 // Iterates over the flattened children of a node, which accounts for anonymous
 // children and nodes moved by insertion points. If a node has anonymous
 // children, those are iterated over.
 class FlattenedChildIterator : public ExplicitChildIterator
 {
 public:
-  FlattenedChildIterator(nsIContent* aParent)
+  explicit FlattenedChildIterator(nsIContent* aParent)
     : ExplicitChildIterator(aParent), mXBLInvolved(false)
   {
     Init(false);
   }
 
   FlattenedChildIterator(FlattenedChildIterator&& aOther)
     : ExplicitChildIterator(Move(aOther)), mXBLInvolved(aOther.mXBLInvolved) {}
 

--- a/content/base/src/Comment.h
+++ b/content/base/src/Comment.h
@@ -21,23 +21,23 @@ private:
   {
     NS_ABORT_IF_FALSE(mNodeInfo->NodeType() == nsIDOMNode::COMMENT_NODE,
                       "Bad NodeType in aNodeInfo");
   }
 
   virtual ~Comment();
 
 public:
-  Comment(already_AddRefed<mozilla::dom::NodeInfo>&& aNodeInfo)
+  explicit Comment(already_AddRefed<mozilla::dom::NodeInfo>&& aNodeInfo)
     : nsGenericDOMDataNode(aNodeInfo)
   {
     Init();
   }
 
-  Comment(nsNodeInfoManager* aNodeInfoManager)
+  explicit Comment(nsNodeInfoManager* aNodeInfoManager)
     : nsGenericDOMDataNode(aNodeInfoManager->GetCommentNodeInfo())
   {
     Init();
   }
 
   // nsISupports
   NS_DECL_ISUPPORTS_INHERITED
 

--- a/content/base/src/DOMMatrix.h
+++ b/content/base/src/DOMMatrix.h
@@ -20,17 +20,17 @@ namespace mozilla {
 namespace dom {
 
 class GlobalObject;
 class DOMMatrix;
 
 class DOMMatrixReadOnly : public nsWrapperCache
 {
 public:
-  DOMMatrixReadOnly(nsISupports* aParent)
+  explicit DOMMatrixReadOnly(nsISupports* aParent)
     : mParent(aParent), mMatrix2D(new gfx::Matrix())
   {
     SetIsDOMBinding();
   }
 
   DOMMatrixReadOnly(nsISupports* aParent, const DOMMatrixReadOnly& other)
     : mParent(aParent)
   {
@@ -139,17 +139,17 @@ private:
   DOMMatrixReadOnly() MOZ_DELETE;
   DOMMatrixReadOnly(const DOMMatrixReadOnly&) MOZ_DELETE;
   DOMMatrixReadOnly& operator=(const DOMMatrixReadOnly&) MOZ_DELETE;
 };
 
 class DOMMatrix MOZ_FINAL : public DOMMatrixReadOnly
 {
 public:
-  DOMMatrix(nsISupports* aParent)
+  explicit DOMMatrix(nsISupports* aParent)
     : DOMMatrixReadOnly(aParent)
   {}
 
   DOMMatrix(nsISupports* aParent, const DOMMatrixReadOnly& other)
     : DOMMatrixReadOnly(aParent, other)
   {}
 
   NS_INLINE_DECL_CYCLE_COLLECTING_NATIVE_REFCOUNTING(DOMMatrix)

--- a/content/base/src/DOMParser.h
+++ b/content/base/src/DOMParser.h
@@ -76,34 +76,34 @@ public:
   }
 
   virtual JSObject* WrapObject(JSContext* aCx) MOZ_OVERRIDE
   {
     return mozilla::dom::DOMParserBinding::Wrap(aCx, this);
   }
 
 private:
-  DOMParser(nsISupports* aOwner) : mOwner(aOwner), mAttemptedInit(false)
+  explicit DOMParser(nsISupports* aOwner) : mOwner(aOwner), mAttemptedInit(false)
   {
     MOZ_ASSERT(aOwner);
     SetIsDOMBinding();
   }
 
   nsresult InitInternal(nsISupports* aOwner, nsIPrincipal* prin,
                         nsIURI* documentURI, nsIURI* baseURI);
 
   nsresult SetUpDocument(DocumentFlavor aFlavor, nsIDOMDocument** aResult);
 
   // Helper for ParseFromString
   nsresult ParseFromString(const nsAString& str, const char *contentType,
                            nsIDOMDocument **aResult);
 
   class AttemptedInitMarker {
   public:
-    AttemptedInitMarker(bool* aAttemptedInit) :
+    explicit AttemptedInitMarker(bool* aAttemptedInit) :
       mAttemptedInit(aAttemptedInit)
     {}
 
     ~AttemptedInitMarker() {
       *mAttemptedInit = true;
     }
 
   private:

--- a/content/base/src/DOMPoint.h
+++ b/content/base/src/DOMPoint.h
@@ -44,18 +44,18 @@ protected:
   double mX, mY, mZ, mW;
 };
 
 class DOMPoint MOZ_FINAL : public DOMPointReadOnly
 {
   ~DOMPoint() {}
 
 public:
-  DOMPoint(nsISupports* aParent, double aX = 0.0, double aY = 0.0,
-           double aZ = 0.0, double aW = 1.0)
+  explicit DOMPoint(nsISupports* aParent, double aX = 0.0, double aY = 0.0,
+                    double aZ = 0.0, double aW = 1.0)
     : DOMPointReadOnly(aParent, aX, aY, aZ, aW)
   {}
 
   NS_INLINE_DECL_CYCLE_COLLECTING_NATIVE_REFCOUNTING(DOMPoint)
   NS_DECL_CYCLE_COLLECTION_SCRIPT_HOLDER_NATIVE_CLASS(DOMPoint)
 
   static already_AddRefed<DOMPoint>
   Constructor(const GlobalObject& aGlobal, const DOMPointInit& aParams,

--- a/content/base/src/DOMQuad.cpp
+++ b/content/base/src/DOMQuad.cpp
@@ -73,17 +73,17 @@ DOMQuad::Constructor(const GlobalObject&
   points[3] = CSSPoint(x, y + h);
   nsRefPtr<DOMQuad> obj = new DOMQuad(aGlobal.GetAsSupports(), points);
   return obj.forget();
 }
 
 class DOMQuad::QuadBounds MOZ_FINAL : public DOMRectReadOnly
 {
 public:
-  QuadBounds(DOMQuad* aQuad)
+  explicit QuadBounds(DOMQuad* aQuad)
     : DOMRectReadOnly(aQuad->GetParentObject())
     , mQuad(aQuad)
   {}
 
   NS_DECL_CYCLE_COLLECTION_CLASS_INHERITED(QuadBounds, DOMRectReadOnly)
   NS_DECL_ISUPPORTS_INHERITED
 
   virtual double X() const

--- a/content/base/src/DOMQuad.h
+++ b/content/base/src/DOMQuad.h
@@ -24,17 +24,17 @@ class DOMPoint;
 struct DOMPointInit;
 
 class DOMQuad MOZ_FINAL : public nsWrapperCache
 {
   ~DOMQuad();
 
 public:
   DOMQuad(nsISupports* aParent, CSSPoint aPoints[4]);
-  DOMQuad(nsISupports* aParent);
+  explicit DOMQuad(nsISupports* aParent);
 
   NS_INLINE_DECL_CYCLE_COLLECTING_NATIVE_REFCOUNTING(DOMQuad)
   NS_DECL_CYCLE_COLLECTION_SCRIPT_HOLDER_NATIVE_CLASS(DOMQuad)
 
   nsISupports* GetParentObject() const { return mParent; }
   virtual JSObject* WrapObject(JSContext* aCx) MOZ_OVERRIDE;
 
   static already_AddRefed<DOMQuad>

--- a/content/base/src/DirectionalityUtils.cpp
+++ b/content/base/src/DirectionalityUtils.cpp
@@ -432,17 +432,17 @@ class nsTextNodeDirectionalityMap
 
     nsTextNodeDirectionalityMap* map =
       reinterpret_cast<nsTextNodeDirectionalityMap * >(aPropertyValue);
     map->EnsureMapIsClear(textNode);
     delete map;
   }
 
 public:
-  nsTextNodeDirectionalityMap(nsINode* aTextNode)
+  explicit nsTextNodeDirectionalityMap(nsINode* aTextNode)
   {
     MOZ_ASSERT(aTextNode, "Null text node");
     MOZ_COUNT_CTOR(nsTextNodeDirectionalityMap);
     aTextNode->SetProperty(nsGkAtoms::textNodeDirectionalityMap, this,
                            nsTextNodeDirectionalityMapDtor);
     aTextNode->SetHasTextNodeDirectionalityMap();
   }
 

--- a/content/base/src/DocumentFragment.h
+++ b/content/base/src/DocumentFragment.h
@@ -45,23 +45,23 @@ public:
   NS_DECL_ISUPPORTS_INHERITED
 
   // interface nsIDOMNode
   NS_FORWARD_NSIDOMNODE_TO_NSINODE
 
   // interface nsIDOMDocumentFragment
   NS_DECL_NSIDOMDOCUMENTFRAGMENT
 
-  DocumentFragment(already_AddRefed<mozilla::dom::NodeInfo>& aNodeInfo)
+  explicit DocumentFragment(already_AddRefed<mozilla::dom::NodeInfo>& aNodeInfo)
     : FragmentOrElement(aNodeInfo), mHost(nullptr)
   {
     Init();
   }
 
-  DocumentFragment(nsNodeInfoManager* aNodeInfoManager)
+  explicit DocumentFragment(nsNodeInfoManager* aNodeInfoManager)
     : FragmentOrElement(aNodeInfoManager->GetNodeInfo(
                                             nsGkAtoms::documentFragmentNodeName,
                                             nullptr, kNameSpaceID_None,
                                             nsIDOMNode::DOCUMENT_FRAGMENT_NODE)),
       mHost(nullptr)
   {
     Init();
   }

--- a/content/base/src/DocumentType.h
+++ b/content/base/src/DocumentType.h
@@ -24,17 +24,17 @@ namespace dom {
 // CharacterData object, even though DocumentType is not character
 // data. This is done simply for convenience and should be changed if
 // this restricts what should be done for character data.
 
 class DocumentTypeForward : public nsGenericDOMDataNode,
                             public nsIDOMDocumentType
 {
 public:
-  DocumentTypeForward(already_AddRefed<mozilla::dom::NodeInfo>& aNodeInfo)
+  explicit DocumentTypeForward(already_AddRefed<mozilla::dom::NodeInfo>& aNodeInfo)
     : nsGenericDOMDataNode(aNodeInfo)
   {
   }
 
   // nsIDOMNode
   NS_FORWARD_NSIDOMNODE_TO_NSINODE
 };
 

--- a/content/base/src/EventSource.cpp
+++ b/content/base/src/EventSource.cpp
@@ -496,17 +496,17 @@ EventSource::OnStopRequest(nsIRequest *a
 
 /**
  * Simple helper class that just forwards the redirect callback back
  * to the EventSource.
  */
 class AsyncVerifyRedirectCallbackFwr MOZ_FINAL : public nsIAsyncVerifyRedirectCallback
 {
 public:
-  AsyncVerifyRedirectCallbackFwr(EventSource* aEventsource)
+  explicit AsyncVerifyRedirectCallbackFwr(EventSource* aEventsource)
     : mEventSource(aEventsource)
   {
   }
 
   NS_DECL_CYCLE_COLLECTING_ISUPPORTS
   NS_DECL_CYCLE_COLLECTION_CLASS(AsyncVerifyRedirectCallbackFwr)
 
   // nsIAsyncVerifyRedirectCallback implementation

--- a/content/base/src/EventSource.h
+++ b/content/base/src/EventSource.h
@@ -41,17 +41,17 @@ class EventSource : public DOMEventTarge
                   , public nsIStreamListener
                   , public nsIChannelEventSink
                   , public nsIInterfaceRequestor
                   , public nsSupportsWeakReference
 {
 friend class AsyncVerifyRedirectCallbackFwr;
 
 public:
-  EventSource(nsPIDOMWindow* aOwnerWindow);
+  explicit EventSource(nsPIDOMWindow* aOwnerWindow);
   NS_DECL_ISUPPORTS_INHERITED
   NS_DECL_CYCLE_COLLECTION_SKIPPABLE_SCRIPT_HOLDER_CLASS_INHERITED(
     EventSource, DOMEventTargetHelper)
 
   NS_DECL_NSIOBSERVER
   NS_DECL_NSISTREAMLISTENER
   NS_DECL_NSIREQUESTOBSERVER
   NS_DECL_NSICHANNELEVENTSINK

--- a/content/base/src/FragmentOrElement.cpp
+++ b/content/base/src/FragmentOrElement.cpp
@@ -2263,17 +2263,17 @@ private:
   Unit* AddUnit()
   {
     if (mLast->mUnits.Length() == STRING_BUFFER_UNITS) {
       new StringBuilder(this);
     }
     return mLast->mUnits.AppendElement();
   }
 
-  StringBuilder(StringBuilder* aFirst)
+  explicit StringBuilder(StringBuilder* aFirst)
   : mLast(nullptr), mLength(0)
   {
     MOZ_COUNT_CTOR(StringBuilder);
     aFirst->mLast->mNext = this;
     aFirst->mLast = this;
   }
 
   void EncodeAttrString(const nsAutoString& aValue, nsAString& aOut)

--- a/content/base/src/ImportManager.cpp
+++ b/content/base/src/ImportManager.cpp
@@ -20,17 +20,17 @@
 #include "nsIDOMEvent.h"
 #include "nsIPrincipal.h"
 #include "nsIScriptObjectPrincipal.h"
 #include "nsScriptLoader.h"
 #include "nsNetUtil.h"
 
 class AutoError {
 public:
-  AutoError(mozilla::dom::ImportLoader* loader, bool scriptsBlocked = true)
+  explicit AutoError(mozilla::dom::ImportLoader* loader, bool scriptsBlocked = true)
     : mLoader(loader)
     , mPassed(false)
     , mScriptsBlocked(scriptsBlocked)
   {}
 
   ~AutoError()
   {
     if (!mPassed) {

--- a/content/base/src/Link.h
+++ b/content/base/src/Link.h
@@ -31,17 +31,17 @@ class Element;
 class Link : public URLSearchParamsObserver
 {
 public:
   NS_DECLARE_STATIC_IID_ACCESSOR(MOZILLA_DOM_LINK_IMPLEMENTATION_IID)
 
   /**
    * aElement is the element pointer corresponding to this link.
    */
-  Link(Element* aElement);
+  explicit Link(Element* aElement);
   virtual void SetLinkState(nsLinkState aState);
 
   /**
    * @return NS_EVENT_STATE_VISITED if this link is visited,
    *         NS_EVENT_STATE_UNVISTED if this link is not visited, or 0 if this
    *         link is not actually a link.
    */
   EventStates LinkState() const;

--- a/content/base/src/NodeIterator.cpp
+++ b/content/base/src/NodeIterator.cpp
@@ -223,17 +223,17 @@ NodeIterator::NextOrPrevNode(NodePointer
         aResult.Throw(NS_ERROR_DOM_INVALID_STATE_ERR);
         return nullptr;
     }
 
     mWorkingPointer = mPointer;
 
     struct AutoClear {
         NodePointer* mPtr;
-        AutoClear(NodePointer* ptr) : mPtr(ptr) {}
+        explicit AutoClear(NodePointer* ptr) : mPtr(ptr) {}
        ~AutoClear() { mPtr->Clear(); }
     } ac(&mWorkingPointer);
 
     while ((mWorkingPointer.*aMove)(mRoot)) {
         nsCOMPtr<nsINode> testNode = mWorkingPointer.mNode;
         int16_t filtered = TestNode(testNode, aResult);
         if (aResult.Failed()) {
             return nullptr;

--- a/content/base/src/ResponsiveImageSelector.h
+++ b/content/base/src/ResponsiveImageSelector.h
@@ -18,17 +18,17 @@ namespace dom {
 
 class ResponsiveImageCandidate;
 
 class ResponsiveImageSelector : public nsISupports
 {
   friend class ResponsiveImageCandidate;
 public:
   NS_DECL_ISUPPORTS
-  ResponsiveImageSelector(nsIContent *aContent);
+  explicit ResponsiveImageSelector(nsIContent* aContent);
 
   // Given a srcset string, parse and replace current candidates (does not
   // replace default source)
   bool SetCandidatesFromSourceSet(const nsAString & aSrcSet);
 
   // Fill the source sizes from a valid sizes descriptor. Returns false if
   // descriptor is invalid.
   bool SetSizesFromDescriptor(const nsAString & aSizesDescriptor);

--- a/content/base/src/ShadowRoot.h
+++ b/content/base/src/ShadowRoot.h
@@ -170,17 +170,17 @@ protected:
   // the insertion points. After this flag is set, nodes will be distributed
   // on the next mutation event.
   bool mInsertionPointChanged;
 };
 
 class ShadowRootStyleSheetList : public StyleSheetList
 {
 public:
-  ShadowRootStyleSheetList(ShadowRoot* aShadowRoot);
+  explicit ShadowRootStyleSheetList(ShadowRoot* aShadowRoot);
 
   NS_DECL_ISUPPORTS_INHERITED
   NS_DECL_CYCLE_COLLECTION_CLASS_INHERITED(ShadowRootStyleSheetList, StyleSheetList)
 
   virtual nsINode* GetParentObject() const MOZ_OVERRIDE
   {
     return mShadowRoot;
   }

--- a/content/base/src/Text.h
+++ b/content/base/src/Text.h
@@ -10,21 +10,21 @@
 #include "mozilla/ErrorResult.h"
 
 namespace mozilla {
 namespace dom {
 
 class Text : public nsGenericDOMDataNode
 {
 public:
-  Text(already_AddRefed<mozilla::dom::NodeInfo>& aNodeInfo)
+  explicit Text(already_AddRefed<mozilla::dom::NodeInfo>& aNodeInfo)
     : nsGenericDOMDataNode(aNodeInfo)
   {}
 
-  Text(already_AddRefed<mozilla::dom::NodeInfo>&& aNodeInfo)
+  explicit Text(already_AddRefed<mozilla::dom::NodeInfo>&& aNodeInfo)
     : nsGenericDOMDataNode(aNodeInfo)
   {}
 
   using nsGenericDOMDataNode::GetWholeText;
 
   // WebIDL API
   already_AddRefed<Text> SplitText(uint32_t aOffset, ErrorResult& rv);
   void GetWholeText(nsAString& aWholeText, ErrorResult& rv)

--- a/content/base/src/WebSocket.cpp
+++ b/content/base/src/WebSocket.cpp
@@ -46,18 +46,18 @@
 namespace mozilla {
 namespace dom {
 
 #define UTF_8_REPLACEMENT_CHAR    static_cast<char16_t>(0xFFFD)
 
 class CallDispatchConnectionCloseEvents: public nsRunnable
 {
 public:
-CallDispatchConnectionCloseEvents(WebSocket* aWebSocket)
-  : mWebSocket(aWebSocket)
+  explicit CallDispatchConnectionCloseEvents(WebSocket* aWebSocket)
+    : mWebSocket(aWebSocket)
   {}
 
   NS_IMETHOD Run()
   {
     mWebSocket->DispatchConnectionCloseEvents();
     return NS_OK;
   }
 
@@ -749,17 +749,17 @@ WebSocket::Init(JSContext* aCx,
 
 //-----------------------------------------------------------------------------
 // WebSocket methods:
 //-----------------------------------------------------------------------------
 
 class nsAutoCloseWS
 {
 public:
-  nsAutoCloseWS(WebSocket* aWebSocket)
+  explicit nsAutoCloseWS(WebSocket* aWebSocket)
     : mWebSocket(aWebSocket)
   {}
 
   ~nsAutoCloseWS()
   {
     if (!mWebSocket->mChannel) {
       mWebSocket->CloseConnection(nsIWebSocketChannel::CLOSE_INTERNAL_ERROR);
     }

--- a/content/base/src/WebSocket.h
+++ b/content/base/src/WebSocket.h
@@ -134,17 +134,17 @@ public: // WebIDL interface:
   void Send(nsIDOMBlob* aData,
             ErrorResult& aRv);
   void Send(const ArrayBuffer& aData,
             ErrorResult& aRv);
   void Send(const ArrayBufferView& aData,
             ErrorResult& aRv);
 
 private: // constructor && distructor
-  WebSocket(nsPIDOMWindow* aOwnerWindow);
+  explicit WebSocket(nsPIDOMWindow* aOwnerWindow);
   virtual ~WebSocket();
 
 protected:
   nsresult Init(JSContext* aCx,
                 nsIPrincipal* aPrincipal,
                 const nsAString& aURL,
                 nsTArray<nsString>& aProtocolArray);
 

--- a/content/base/src/nsAttrValueOrString.h
+++ b/content/base/src/nsAttrValueOrString.h
@@ -16,22 +16,22 @@
 #define nsAttrValueOrString_h___
 
 #include "nsString.h"
 #include "nsAttrValue.h"
 
 class MOZ_STACK_CLASS nsAttrValueOrString
 {
 public:
-  nsAttrValueOrString(const nsAString& aValue)
+  explicit nsAttrValueOrString(const nsAString& aValue)
     : mAttrValue(nullptr)
     , mStringPtr(&aValue)
     , mCheapString(nullptr)
   { }
-  nsAttrValueOrString(const nsAttrValue& aValue)
+  explicit nsAttrValueOrString(const nsAttrValue& aValue)
     : mAttrValue(&aValue)
     , mStringPtr(nullptr)
     , mCheapString(nullptr)
   { }
 
   /**
    * Returns a reference to the string value of the contents of this object.
    *

--- a/content/base/src/nsCSPUtils.h
+++ b/content/base/src/nsCSPUtils.h
@@ -193,31 +193,31 @@ class nsCSPBaseSrc {
     virtual bool allows(enum CSPKeyword aKeyword, const nsAString& aHashOrNonce) const;
     virtual void toString(nsAString& outStr) const = 0;
 };
 
 /* =============== nsCSPSchemeSrc ============ */
 
 class nsCSPSchemeSrc : public nsCSPBaseSrc {
   public:
-    nsCSPSchemeSrc(const nsAString& aScheme);
+    explicit nsCSPSchemeSrc(const nsAString& aScheme);
     virtual ~nsCSPSchemeSrc();
 
     bool permits(nsIURI* aUri, const nsAString& aNonce) const;
     void toString(nsAString& outStr) const;
 
   private:
     nsString mScheme;
 };
 
 /* =============== nsCSPHostSrc ============== */
 
 class nsCSPHostSrc : public nsCSPBaseSrc {
   public:
-    nsCSPHostSrc(const nsAString& aHost);
+    explicit nsCSPHostSrc(const nsAString& aHost);
     virtual ~nsCSPHostSrc();
 
     bool permits(nsIURI* aUri, const nsAString& aNonce) const;
     void toString(nsAString& outStr) const;
 
     void setScheme(const nsAString& aScheme);
     void setPort(const nsAString& aPort);
     void appendPath(const nsAString &aPath);
@@ -230,31 +230,31 @@ class nsCSPHostSrc : public nsCSPBaseSrc
     nsString mPath;
     nsString mFileAndArguments;
 };
 
 /* =============== nsCSPKeywordSrc ============ */
 
 class nsCSPKeywordSrc : public nsCSPBaseSrc {
   public:
-    nsCSPKeywordSrc(CSPKeyword aKeyword);
+    explicit nsCSPKeywordSrc(CSPKeyword aKeyword);
     virtual ~nsCSPKeywordSrc();
 
     bool allows(enum CSPKeyword aKeyword, const nsAString& aHashOrNonce) const;
     void toString(nsAString& outStr) const;
 
   private:
     CSPKeyword mKeyword;
 };
 
 /* =============== nsCSPNonceSource =========== */
 
 class nsCSPNonceSrc : public nsCSPBaseSrc {
   public:
-    nsCSPNonceSrc(const nsAString& aNonce);
+    explicit nsCSPNonceSrc(const nsAString& aNonce);
     virtual ~nsCSPNonceSrc();
 
     bool permits(nsIURI* aUri, const nsAString& aNonce) const;
     bool allows(enum CSPKeyword aKeyword, const nsAString& aHashOrNonce) const;
     void toString(nsAString& outStr) const;
 
   private:
     nsString mNonce;
@@ -274,31 +274,31 @@ class nsCSPHashSrc : public nsCSPBaseSrc
     nsString mAlgorithm;
     nsString mHash;
 };
 
 /* =============== nsCSPReportURI ============ */
 
 class nsCSPReportURI : public nsCSPBaseSrc {
   public:
-    nsCSPReportURI(nsIURI *aURI);
+    explicit nsCSPReportURI(nsIURI* aURI);
     virtual ~nsCSPReportURI();
 
     void toString(nsAString& outStr) const;
 
   private:
     nsCOMPtr<nsIURI> mReportURI;
 };
 
 /* =============== nsCSPDirective ============= */
 
 class nsCSPDirective {
   public:
     nsCSPDirective();
-    nsCSPDirective(enum CSPDirective aDirective);
+    explicit nsCSPDirective(enum CSPDirective aDirective);
     virtual ~nsCSPDirective();
 
     bool permits(nsIURI* aUri, const nsAString& aNonce) const;
     bool allows(enum CSPKeyword aKeyword, const nsAString& aHashOrNonce) const;
     void toString(nsAString& outStr) const;
 
     inline void addSrcs(const nsTArray<nsCSPBaseSrc*>& aSrcs)
       { mSrcs = aSrcs; }

--- a/content/base/src/nsContentList.h
+++ b/content/base/src/nsContentList.h
@@ -112,18 +112,18 @@ protected:
 
   nsTArray< nsCOMPtr<nsIContent> > mElements;
 };
 
 
 class nsSimpleContentList : public nsBaseContentList
 {
 public:
-  nsSimpleContentList(nsINode *aRoot) : nsBaseContentList(),
-                                        mRoot(aRoot)
+  explicit nsSimpleContentList(nsINode* aRoot) : nsBaseContentList(),
+                                                 mRoot(aRoot)
   {
   }
 
   NS_DECL_ISUPPORTS_INHERITED
   NS_DECL_CYCLE_COLLECTION_CLASS_INHERITED(nsSimpleContentList,
                                            nsBaseContentList)
 
   virtual nsINode* GetParentObject() MOZ_OVERRIDE

--- a/content/base/src/nsContentUtils.cpp
+++ b/content/base/src/nsContentUtils.cpp
@@ -349,17 +349,17 @@ public:
   }
 };
 
 NS_IMPL_ISUPPORTS(DOMEventListenerManagersHashReporter, nsIMemoryReporter)
 
 class EventListenerManagerMapEntry : public PLDHashEntryHdr
 {
 public:
-  EventListenerManagerMapEntry(const void *aKey)
+  explicit EventListenerManagerMapEntry(const void* aKey)
     : mKey(aKey)
   {
   }
 
   ~EventListenerManagerMapEntry()
   {
     NS_ASSERTION(!mListenerManager, "caller must release and disconnect ELM");
   }
@@ -1287,49 +1287,49 @@ nsContentUtils::GetBidiKeyboard()
 }
 
 template <class OutputIterator>
 struct NormalizeNewlinesCharTraits {
   public:
     typedef typename OutputIterator::value_type value_type;
 
   public:
-    NormalizeNewlinesCharTraits(OutputIterator& aIterator) : mIterator(aIterator) { }
+    explicit NormalizeNewlinesCharTraits(OutputIterator& aIterator) : mIterator(aIterator) { }
     void writechar(typename OutputIterator::value_type aChar) {
       *mIterator++ = aChar;
     }
 
   private:
     OutputIterator mIterator;
 };
 
 template <class CharT>
 struct NormalizeNewlinesCharTraits<CharT*> {
   public:
     typedef CharT value_type;
 
   public:
-    NormalizeNewlinesCharTraits(CharT* aCharPtr) : mCharPtr(aCharPtr) { }
+    explicit NormalizeNewlinesCharTraits(CharT* aCharPtr) : mCharPtr(aCharPtr) { }
     void writechar(CharT aChar) {
       *mCharPtr++ = aChar;
     }
 
   private:
     CharT* mCharPtr;
 };
 
 template <class OutputIterator>
 class CopyNormalizeNewlines
 {
   public:
     typedef typename OutputIterator::value_type value_type;
 
   public:
-    CopyNormalizeNewlines(OutputIterator* aDestination,
-                          bool aLastCharCR=false) :
+    explicit CopyNormalizeNewlines(OutputIterator* aDestination,
+                                   bool aLastCharCR = false) :
       mLastCharCR(aLastCharCR),
       mDestination(aDestination),
       mWritten(0)
     { }
 
     uint32_t GetCharsWritten() {
       return mWritten;
     }
@@ -4541,22 +4541,22 @@ nsContentUtils::IsInSameAnonymousTree(co
       aContent->GetContainingShadow();
   }
 
   return nodeAsContent->GetBindingParent() == aContent->GetBindingParent();
 }
 
 class AnonymousContentDestroyer : public nsRunnable {
 public:
-  AnonymousContentDestroyer(nsCOMPtr<nsIContent>* aContent) {
+  explicit AnonymousContentDestroyer(nsCOMPtr<nsIContent>* aContent) {
     mContent.swap(*aContent);
     mParent = mContent->GetParent();
     mDoc = mContent->OwnerDoc();
   }
-  AnonymousContentDestroyer(nsCOMPtr<Element>* aElement) {
+  explicit AnonymousContentDestroyer(nsCOMPtr<Element>* aElement) {
     mContent = aElement->forget();
     mParent = mContent->GetParent();
     mDoc = mContent->OwnerDoc();
   }
   NS_IMETHOD Run() {
     mContent->UnbindFromTree();
     return NS_OK;
   }

--- a/content/base/src/nsCrossSiteListenerProxy.cpp
+++ b/content/base/src/nsCrossSiteListenerProxy.cpp
@@ -119,17 +119,17 @@ public:
   struct TokenTime
   {
     nsCString token;
     TimeStamp expirationTime;
   };
 
   struct CacheEntry : public LinkedListElement<CacheEntry>
   {
-    CacheEntry(nsCString& aKey)
+    explicit CacheEntry(nsCString& aKey)
       : mKey(aKey)
     {
       MOZ_COUNT_CTOR(nsPreflightCache::CacheEntry);
     }
     
     ~CacheEntry()
     {
       MOZ_COUNT_DTOR(nsPreflightCache::CacheEntry);

--- a/content/base/src/nsDOMSerializer.h
+++ b/content/base/src/nsDOMSerializer.h
@@ -51,17 +51,17 @@ public:
   virtual JSObject* WrapObject(JSContext* aCx) MOZ_OVERRIDE
   {
     return mozilla::dom::XMLSerializerBinding::Wrap(aCx, this);
   }
 
 private:
   virtual ~nsDOMSerializer();
 
-  nsDOMSerializer(nsISupports* aOwner) : mOwner(aOwner)
+  explicit nsDOMSerializer(nsISupports* aOwner) : mOwner(aOwner)
   {
     MOZ_ASSERT(aOwner);
     SetIsDOMBinding();
   }
 
   nsCOMPtr<nsISupports> mOwner;
 };
 

--- a/content/base/src/nsDocument.cpp
+++ b/content/base/src/nsDocument.cpp
@@ -679,17 +679,17 @@ class SubDocMapEntry : public PLDHashEnt
 public:
   // Both of these are strong references
   Element *mKey; // must be first, to look like PLDHashEntryStub
   nsIDocument *mSubDocument;
 };
 
 struct FindContentData
 {
-  FindContentData(nsIDocument *aSubDoc)
+  explicit FindContentData(nsIDocument* aSubDoc)
     : mSubDocument(aSubDoc), mResult(nullptr)
   {
   }
 
   nsISupports *mSubDocument;
   Element *mResult;
 };
 
@@ -1393,17 +1393,17 @@ nsExternalResourceMap::ExternalResource:
 // ==================================================================
 
 // If we ever have an nsIDocumentObserver notification for stylesheet title
 // changes we should update the list from that instead of overriding
 // EnsureFresh.
 class nsDOMStyleSheetSetList MOZ_FINAL : public DOMStringList
 {
 public:
-  nsDOMStyleSheetSetList(nsIDocument* aDocument);
+  explicit nsDOMStyleSheetSetList(nsIDocument* aDocument);
 
   void Disconnect()
   {
     mDocument = nullptr;
   }
 
   virtual void EnsureFresh() MOZ_OVERRIDE;
 
@@ -5541,17 +5541,17 @@ nsDocument::RegisterUnresolvedElement(El
 }
 
 namespace {
 
 class ProcessStackRunner MOZ_FINAL : public nsIRunnable
 {
   ~ProcessStackRunner() {}
 public:
-  ProcessStackRunner(bool aIsBaseQueue = false)
+  explicit ProcessStackRunner(bool aIsBaseQueue = false)
     : mIsBaseQueue(aIsBaseQueue)
   {
   }
   NS_DECL_ISUPPORTS
   NS_IMETHOD Run() MOZ_OVERRIDE
   {
     nsDocument::ProcessTopElementQueue(mIsBaseQueue);
     return NS_OK;
@@ -8710,17 +8710,17 @@ nsDocument::UnblockOnload(bool aFireSync
                                  false);
       asyncDispatcher->PostDOMEvent();
     }
   }
 }
 
 class nsUnblockOnloadEvent : public nsRunnable {
 public:
-  nsUnblockOnloadEvent(nsDocument *doc) : mDoc(doc) {}
+  explicit nsUnblockOnloadEvent(nsDocument* aDoc) : mDoc(aDoc) {}
   NS_IMETHOD Run() {
     mDoc->DoUnblockOnload();
     return NS_OK;
   }
 private:
   nsRefPtr<nsDocument> mDoc;
 };
 
@@ -9419,17 +9419,17 @@ nsDocument::LoadChromeSheetSync(nsIURI* 
                                 CSSStyleSheet** sheet)
 {
   return CSSLoader()->LoadSheetSync(uri, isAgentSheet, isAgentSheet, sheet);
 }
 
 class nsDelayedEventDispatcher : public nsRunnable
 {
 public:
-  nsDelayedEventDispatcher(nsTArray<nsCOMPtr<nsIDocument> >& aDocuments)
+  explicit nsDelayedEventDispatcher(nsTArray<nsCOMPtr<nsIDocument>>& aDocuments)
   {
     mDocuments.SwapElements(aDocuments);
   }
   virtual ~nsDelayedEventDispatcher() {}
 
   NS_IMETHOD Run()
   {
     FireOrClearDelayedEvents(mDocuments, true);
@@ -9439,17 +9439,17 @@ public:
 private:
   nsTArray<nsCOMPtr<nsIDocument> > mDocuments;
 };
 
 namespace {
 
 struct UnsuppressArgs
 {
-  UnsuppressArgs(nsIDocument::SuppressionType aWhat)
+  explicit UnsuppressArgs(nsIDocument::SuppressionType aWhat)
     : mWhat(aWhat)
   {
   }
 
   nsIDocument::SuppressionType mWhat;
   nsTArray<nsCOMPtr<nsIDocument>> mDocs;
 };
 
@@ -10542,17 +10542,17 @@ SetWindowFullScreen(nsIDocument* aDoc, b
   }
   if (!nsContentUtils::IsFullscreenApiContentOnly()) {
     nsContentUtils::AddScriptRunner(new nsSetWindowFullScreen(aDoc, aValue));
   }
 }
 
 class nsCallExitFullscreen : public nsRunnable {
 public:
-  nsCallExitFullscreen(nsIDocument* aDoc)
+  explicit nsCallExitFullscreen(nsIDocument* aDoc)
     : mDoc(aDoc) {}
   NS_IMETHOD Run()
   {
     nsDocument::ExitFullscreen(mDoc);
     return NS_OK;
   }
 private:
   nsCOMPtr<nsIDocument> mDoc;
@@ -10856,17 +10856,17 @@ bool
 nsDocument::IsFullScreenDoc()
 {
   return GetFullScreenElement() != nullptr;
 }
 
 class nsCallRequestFullScreen : public nsRunnable
 {
 public:
-  nsCallRequestFullScreen(Element* aElement)
+  explicit nsCallRequestFullScreen(Element* aElement)
     : mElement(aElement),
       mDoc(aElement->OwnerDoc()),
       mWasCallerChrome(nsContentUtils::IsCallerChrome()),
       mHadRequestPending(static_cast<nsDocument*>(mDoc.get())->
                            mAsyncFullscreenPending)
   {
     static_cast<nsDocument*>(mDoc.get())->
       mAsyncFullscreenPending = true;

--- a/content/base/src/nsDocument.h
+++ b/content/base/src/nsDocument.h
@@ -117,22 +117,22 @@ class CallbackFunction;
  * the ID's nsIdentifierMapEntry, the document.all result is released too.
  * Perhaps the document.all results should have their own hashtable
  * in nsHTMLDocument.
  */
 class nsIdentifierMapEntry : public nsStringHashKey
 {
 public:
   typedef mozilla::dom::Element Element;
-  
-  nsIdentifierMapEntry(const nsAString& aKey) :
+
+  explicit nsIdentifierMapEntry(const nsAString& aKey) :
     nsStringHashKey(&aKey), mNameContentList(nullptr)
   {
   }
-  nsIdentifierMapEntry(const nsAString *aKey) :
+  explicit nsIdentifierMapEntry(const nsAString* aKey) :
     nsStringHashKey(aKey), mNameContentList(nullptr)
   {
   }
   nsIdentifierMapEntry(const nsIdentifierMapEntry& aOther) :
     nsStringHashKey(&aOther.GetKey())
   {
     NS_ERROR("Should never be called");
   }
@@ -198,18 +198,18 @@ public:
     void* mData;
     bool mForImage;
   };
 
   struct ChangeCallbackEntry : public PLDHashEntryHdr {
     typedef const ChangeCallback KeyType;
     typedef const ChangeCallback* KeyTypePointer;
 
-    ChangeCallbackEntry(const ChangeCallback* key) :
-      mKey(*key) { }
+    explicit ChangeCallbackEntry(const ChangeCallback* aKey) :
+      mKey(*aKey) { }
     ChangeCallbackEntry(const ChangeCallbackEntry& toCopy) :
       mKey(toCopy.mKey) { }
 
     KeyType GetKey() const { return mKey; }
     bool KeyEquals(KeyTypePointer aKey) const {
       return aKey->mCallback == mKey.mCallback &&
              aKey->mData == mKey.mData &&
              aKey->mForImage == mKey.mForImage;
@@ -247,17 +247,17 @@ class CustomElementHashKey : public PLDH
 public:
   typedef CustomElementHashKey *KeyType;
   typedef const CustomElementHashKey *KeyTypePointer;
 
   CustomElementHashKey(int32_t aNamespaceID, nsIAtom *aAtom)
     : mNamespaceID(aNamespaceID),
       mAtom(aAtom)
   {}
-  CustomElementHashKey(const CustomElementHashKey *aKey)
+  explicit CustomElementHashKey(const CustomElementHashKey* aKey)
     : mNamespaceID(aKey->mNamespaceID),
       mAtom(aKey->mAtom)
   {}
   ~CustomElementHashKey()
   {}
 
   KeyType GetKey() const { return const_cast<KeyType>(this); }
   bool KeyEquals(const KeyTypePointer aKey) const
@@ -321,17 +321,17 @@ private:
   // callback queue.
   CustomElementData* mOwnerData;
 };
 
 // Each custom element has an associated callback queue and an element is
 // being created flag.
 struct CustomElementData
 {
-  CustomElementData(nsIAtom* aType);
+  explicit CustomElementData(nsIAtom* aType);
   // Objects in this array are transient and empty after each microtask
   // checkpoint.
   nsTArray<nsAutoPtr<CustomElementCallback>> mCallbackQueue;
   // Custom element type, for <button is="x-button"> or <x-button>
   // this would be x-button.
   nsCOMPtr<nsIAtom> mType;
   // The callback that is next to be processed upon calling RunCallbackQueue.
   int32_t mCurrentCallback;
@@ -433,17 +433,17 @@ public:
   nsString          mData;
   nsDocHeaderData*  mNext;
 };
 
 class nsDOMStyleSheetList : public mozilla::dom::StyleSheetList,
                             public nsStubDocumentObserver
 {
 public:
-  nsDOMStyleSheetList(nsIDocument *aDocument);
+  explicit nsDOMStyleSheetList(nsIDocument* aDocument);
 
   NS_DECL_ISUPPORTS_INHERITED
 
   // nsIDocumentObserver
   NS_DECL_NSIDOCUMENTOBSERVER_STYLESHEETADDED
   NS_DECL_NSIDOCUMENTOBSERVER_STYLESHEETREMOVED
 
   // nsIMutationObserver
@@ -536,17 +536,17 @@ public:
 
 protected:
   class PendingLoad : public ExternalResourceLoad,
                       public nsIStreamListener
   {
     ~PendingLoad() {}
 
   public:
-    PendingLoad(nsDocument* aDisplayDocument) :
+    explicit PendingLoad(nsDocument* aDisplayDocument) :
       mDisplayDocument(aDisplayDocument)
     {}
 
     NS_DECL_ISUPPORTS
     NS_DECL_NSISTREAMLISTENER
     NS_DECL_NSIREQUESTOBSERVER
 
     /**
@@ -568,17 +568,17 @@ protected:
     nsCOMPtr<nsIURI> mURI;
   };
   friend class PendingLoad;
 
   class LoadgroupCallbacks MOZ_FINAL : public nsIInterfaceRequestor
   {
     ~LoadgroupCallbacks() {}
   public:
-    LoadgroupCallbacks(nsIInterfaceRequestor* aOtherCallbacks)
+    explicit LoadgroupCallbacks(nsIInterfaceRequestor* aOtherCallbacks)
       : mCallbacks(aOtherCallbacks)
     {}
     NS_DECL_ISUPPORTS
     NS_DECL_NSIINTERFACEREQUESTOR
   private:
     // The only reason it's safe to hold a strong ref here without leaking is
     // that the notificationCallbacks on a loadgroup aren't the docshell itself
     // but a shim that holds a weak reference to the docshell.
@@ -1442,17 +1442,17 @@ protected:
 #define NS_DOCUMENT_NOTIFY_OBSERVERS(func_, params_)                        \
   NS_OBSERVER_ARRAY_NOTIFY_XPCOM_OBSERVERS(mObservers, nsIDocumentObserver, \
                                            func_, params_);
 
 #ifdef DEBUG
   void VerifyRootContentState();
 #endif
 
-  nsDocument(const char* aContentType);
+  explicit nsDocument(const char* aContentType);
   virtual ~nsDocument();
 
   void EnsureOnloadBlocker();
 
   void NotifyStyleSheetApplicableStateChanged();
 
   nsTArray<nsIObserver*> mCharSetObservers;
 
@@ -1758,17 +1758,17 @@ private:
 public:
   bool mWillReparent;
 #endif
 };
 
 class nsDocumentOnStack
 {
 public:
-  nsDocumentOnStack(nsDocument* aDoc) : mDoc(aDoc)
+  explicit nsDocumentOnStack(nsDocument* aDoc) : mDoc(aDoc)
   {
     mDoc->IncreaseStackRefCnt();
   }
   ~nsDocumentOnStack()
   {
     mDoc->DecreaseStackRefCnt();
   }
 private:

--- a/content/base/src/nsElementFrameLoaderOwner.h
+++ b/content/base/src/nsElementFrameLoaderOwner.h
@@ -26,17 +26,17 @@ class Element;
 class nsXULElement;
 
 /**
  * A helper class for frame elements
  */
 class nsElementFrameLoaderOwner : public nsIFrameLoaderOwner
 {
 public:
-  nsElementFrameLoaderOwner(mozilla::dom::FromParser aFromParser)
+  explicit nsElementFrameLoaderOwner(mozilla::dom::FromParser aFromParser)
     : mNetworkCreated(aFromParser == mozilla::dom::FROM_PARSER_NETWORK)
     , mBrowserFrameListenersRegistered(false)
     , mFrameLoaderCreationDisallowed(false)
   {
   }
 
   virtual ~nsElementFrameLoaderOwner();
 

--- a/content/base/src/nsFormData.h
+++ b/content/base/src/nsFormData.h
@@ -29,17 +29,17 @@ class GlobalObject;
 class nsFormData : public nsIDOMFormData,
                    public nsIXHRSendable,
                    public nsFormSubmission,
                    public nsWrapperCache
 {
   ~nsFormData() {}
 
 public:
-  nsFormData(nsISupports* aOwner = nullptr);
+  explicit nsFormData(nsISupports* aOwner = nullptr);
 
   NS_DECL_CYCLE_COLLECTING_ISUPPORTS
   NS_DECL_CYCLE_COLLECTION_SCRIPT_HOLDER_CLASS_AMBIGUOUS(nsFormData,
                                                          nsIDOMFormData)
 
   NS_DECL_NSIDOMFORMDATA
   NS_DECL_NSIXHRSENDABLE
 

--- a/content/base/src/nsFrameLoader.cpp
+++ b/content/base/src/nsFrameLoader.cpp
@@ -101,17 +101,17 @@ using namespace mozilla::dom;
 using namespace mozilla::dom::ipc;
 using namespace mozilla::layers;
 using namespace mozilla::layout;
 typedef FrameMetrics::ViewID ViewID;
 
 class nsAsyncDocShellDestroyer : public nsRunnable
 {
 public:
-  nsAsyncDocShellDestroyer(nsIDocShell* aDocShell)
+  explicit nsAsyncDocShellDestroyer(nsIDocShell* aDocShell)
     : mDocShell(aDocShell)
   {
   }
 
   NS_IMETHOD Run()
   {
     nsCOMPtr<nsIBaseWindow> base_win(do_QueryInterface(mDocShell));
     if (base_win) {
@@ -303,17 +303,17 @@ nsFrameLoader::ReallyStartLoading()
   }
   
   return rv;
 }
 
 class DelayedStartLoadingRunnable : public nsRunnable
 {
 public:
-  DelayedStartLoadingRunnable(nsFrameLoader* aFrameLoader)
+  explicit DelayedStartLoadingRunnable(nsFrameLoader* aFrameLoader)
     : mFrameLoader(aFrameLoader)
   {
   }
 
   NS_IMETHOD Run()
   {
     // Retry the request.
     mFrameLoader->ReallyStartLoading();
@@ -703,17 +703,17 @@ AllDescendantsOfType(nsIDocShellTreeItem
  * A class that automatically sets mInShow to false when it goes
  * out of scope.
  */
 class MOZ_STACK_CLASS AutoResetInShow {
   private:
     nsFrameLoader* mFrameLoader;
     MOZ_DECL_USE_GUARD_OBJECT_NOTIFIER
   public:
-    AutoResetInShow(nsFrameLoader* aFrameLoader MOZ_GUARD_OBJECT_NOTIFIER_PARAM)
+    explicit AutoResetInShow(nsFrameLoader* aFrameLoader MOZ_GUARD_OBJECT_NOTIFIER_PARAM)
       : mFrameLoader(aFrameLoader)
     {
       MOZ_GUARD_OBJECT_NOTIFIER_INIT;
     }
     ~AutoResetInShow() { mFrameLoader->mInShow = false; }
 };
 
 

--- a/content/base/src/nsFrameMessageManager.cpp
+++ b/content/base/src/nsFrameMessageManager.cpp
@@ -888,17 +888,17 @@ nsFrameMessageManager::AssertAppHasStatu
   *aHasStatus = mCallback->CheckAppHasStatus(aStatus);
 
   return NS_OK;
 }
 
 class MMListenerRemover
 {
 public:
-  MMListenerRemover(nsFrameMessageManager* aMM)
+  explicit MMListenerRemover(nsFrameMessageManager* aMM)
     : mWasHandlingMessage(aMM->mHandlingMessage)
     , mMM(aMM)
   {
     mMM->mHandlingMessage = true;
   }
   ~MMListenerRemover()
   {
     if (!mWasHandlingMessage) {

--- a/content/base/src/nsGenConImageContent.cpp
+++ b/content/base/src/nsGenConImageContent.cpp
@@ -19,17 +19,17 @@
 #include "mozilla/EventStates.h"
 
 using namespace mozilla;
 
 class nsGenConImageContent MOZ_FINAL : public nsXMLElement,
                                        public nsImageLoadingContent
 {
 public:
-  nsGenConImageContent(already_AddRefed<mozilla::dom::NodeInfo>& aNodeInfo)
+  explicit nsGenConImageContent(already_AddRefed<mozilla::dom::NodeInfo>& aNodeInfo)
     : nsXMLElement(aNodeInfo)
   {
     // nsImageLoadingContent starts out broken, so we start out
     // suppressed to match it.
     AddStatesSilently(NS_EVENT_STATE_SUPPRESSED);
   }
 
   nsresult Init(imgRequestProxy* aImageRequest)

--- a/content/base/src/nsGenericDOMDataNode.h
+++ b/content/base/src/nsGenericDOMDataNode.h
@@ -60,18 +60,18 @@ ASSERT_NODE_FLAGS_SPACE(NODE_TYPE_SPECIF
 
 class nsGenericDOMDataNode : public nsIContent
 {
 public:
   NS_DECL_CYCLE_COLLECTING_ISUPPORTS
 
   NS_DECL_SIZEOF_EXCLUDING_THIS
 
-  nsGenericDOMDataNode(already_AddRefed<mozilla::dom::NodeInfo>& aNodeInfo);
-  nsGenericDOMDataNode(already_AddRefed<mozilla::dom::NodeInfo>&& aNodeInfo);
+  explicit nsGenericDOMDataNode(already_AddRefed<mozilla::dom::NodeInfo>& aNodeInfo);
+  explicit nsGenericDOMDataNode(already_AddRefed<mozilla::dom::NodeInfo>&& aNodeInfo);
 
   virtual void GetNodeValueInternal(nsAString& aNodeValue) MOZ_OVERRIDE;
   virtual void SetNodeValueInternal(const nsAString& aNodeValue,
                                     mozilla::ErrorResult& aError) MOZ_OVERRIDE;
 
   // Implementation for nsIDOMCharacterData
   nsresult GetData(nsAString& aData) const;
   nsresult SetData(const nsAString& aData);

--- a/content/base/src/nsHostObjectURI.h
+++ b/content/base/src/nsHostObjectURI.h
@@ -17,17 +17,17 @@
  * These URIs refer to host objects: Blobs, with scheme "blob",
  * MediaStreams, with scheme "mediastream", and MediaSources, with scheme
  * "mediasource".
  */
 class nsHostObjectURI : public nsSimpleURI,
                         public nsIURIWithPrincipal
 {
 public:
-  nsHostObjectURI(nsIPrincipal* aPrincipal) :
+  explicit nsHostObjectURI(nsIPrincipal* aPrincipal) :
       nsSimpleURI(), mPrincipal(aPrincipal)
   {}
 
   // For use only from deserialization
   nsHostObjectURI() : nsSimpleURI() {}
 
   NS_DECL_ISUPPORTS_INHERITED
   NS_DECL_NSIURIWITHPRINCIPAL

--- a/content/base/src/nsImageLoadingContent.cpp
+++ b/content/base/src/nsImageLoadingContent.cpp
@@ -1195,17 +1195,17 @@ nsImageLoadingContent::PreparePendingReq
   return mPendingRequest;
 }
 
 namespace {
 
 class ImageRequestAutoLock
 {
 public:
-  ImageRequestAutoLock(imgIRequest* aRequest)
+  explicit ImageRequestAutoLock(imgIRequest* aRequest)
     : mRequest(aRequest)
   {
     if (mRequest) {
       mRequest->LockImage();
     }
   }
 
   ~ImageRequestAutoLock()

--- a/content/base/src/nsImageLoadingContent.h
+++ b/content/base/src/nsImageLoadingContent.h
@@ -191,17 +191,17 @@ protected:
   void OnUnlockedDraw();
   nsresult OnImageIsAnimated(imgIRequest *aRequest);
 
 private:
   /**
    * Struct used to manage the image observers.
    */
   struct ImageObserver {
-    ImageObserver(imgINotificationObserver* aObserver);
+    explicit ImageObserver(imgINotificationObserver* aObserver);
     ~ImageObserver();
 
     nsCOMPtr<imgINotificationObserver> mObserver;
     ImageObserver* mNext;
   };
 
   /**
    * Struct to report state changes

--- a/content/base/src/nsObjectLoadingContent.cpp
+++ b/content/base/src/nsObjectLoadingContent.cpp
@@ -124,17 +124,17 @@ InActiveDocument(nsIContent *aContent)
 }
 
 ///
 /// Runnables and helper classes
 ///
 
 class nsAsyncInstantiateEvent : public nsRunnable {
 public:
-  nsAsyncInstantiateEvent(nsObjectLoadingContent *aContent)
+  explicit nsAsyncInstantiateEvent(nsObjectLoadingContent* aContent)
   : mContent(aContent) {}
 
   ~nsAsyncInstantiateEvent() {}
 
   NS_IMETHOD Run();
 
 private:
   nsCOMPtr<nsIObjectLoadingContent> mContent;
@@ -157,17 +157,17 @@ nsAsyncInstantiateEvent::Run()
 }
 
 // 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)
+  explicit CheckPluginStopEvent(nsObjectLoadingContent* aContent)
   : mContent(aContent) {}
 
   ~CheckPluginStopEvent() {}
 
   NS_IMETHOD Run();
 
 private:
   nsCOMPtr<nsIObjectLoadingContent> mContent;
@@ -454,27 +454,27 @@ nsStopPluginRunnable::Run()
 }
 
 // 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)
+  explicit 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)
+  explicit AutoSetLoadingToFalse(nsObjectLoadingContent* aContent)
     : mContent(aContent) {}
   ~AutoSetLoadingToFalse() { mContent->mIsLoading = false; }
 private:
   nsObjectLoadingContent* mContent;
 };
 
 ///
 /// Helper functions
@@ -1336,17 +1336,17 @@ public:
   // 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)
+  explicit ObjectInterfaceRequestorShim(nsIObjectLoadingContent* aContent)
     : mContent(aContent)
   {}
 
 protected:
   ~ObjectInterfaceRequestorShim() {}
   nsCOMPtr<nsIObjectLoadingContent> mContent;
 };
 

--- a/content/base/src/nsObjectLoadingContent.h
+++ b/content/base/src/nsObjectLoadingContent.h
@@ -506,17 +506,17 @@ class nsObjectLoadingContent : public ns
 
     // Helper class for SetupProtoChain
     class SetupProtoChainRunner MOZ_FINAL : public nsIRunnable
     {
       ~SetupProtoChainRunner();
     public:
       NS_DECL_ISUPPORTS
 
-      SetupProtoChainRunner(nsObjectLoadingContent* aContent);
+      explicit SetupProtoChainRunner(nsObjectLoadingContent* aContent);
 
       NS_IMETHOD Run() MOZ_OVERRIDE;
 
     private:
       // We store an nsIObjectLoadingContent because we can
       // unambiguously refcount that.
       nsRefPtr<nsIObjectLoadingContent> mContent;
     };

--- a/content/base/src/nsScriptElement.h
+++ b/content/base/src/nsScriptElement.h
@@ -24,17 +24,17 @@ public:
   NS_DECL_NSISCRIPTLOADEROBSERVER
 
   // nsIMutationObserver
   NS_DECL_NSIMUTATIONOBSERVER_CHARACTERDATACHANGED
   NS_DECL_NSIMUTATIONOBSERVER_ATTRIBUTECHANGED
   NS_DECL_NSIMUTATIONOBSERVER_CONTENTAPPENDED
   NS_DECL_NSIMUTATIONOBSERVER_CONTENTINSERTED
 
-  nsScriptElement(mozilla::dom::FromParser aFromParser)
+  explicit nsScriptElement(mozilla::dom::FromParser aFromParser)
     : nsIScriptElement(aFromParser)
   {
   }
 
   virtual nsresult FireErrorEvent() MOZ_OVERRIDE;
 
 protected:
   // Internal methods

--- a/content/base/src/nsScriptLoader.h
+++ b/content/base/src/nsScriptLoader.h
@@ -55,17 +55,17 @@ class nsScriptLoader : public nsIStreamL
     nsCOMPtr<nsIScriptElement> mOldScript;
     nsScriptLoader* mScriptLoader;
   };
 
   friend class nsScriptRequestProcessor;
   friend class AutoCurrentScriptUpdater;
 
 public:
-  nsScriptLoader(nsIDocument* aDocument);
+  explicit nsScriptLoader(nsIDocument* aDocument);
 
   NS_DECL_ISUPPORTS
   NS_DECL_NSISTREAMLOADEROBSERVER
 
   /**
    * The loader maintains a weak reference to the document with
    * which it is initialized. This call forces the reference to
    * be dropped.
@@ -367,17 +367,17 @@ private:
   bool mDeferEnabled;
   bool mDocumentParsingDone;
   bool mBlockingDOMContentLoaded;
 };
 
 class nsAutoScriptLoaderDisabler
 {
 public:
-  nsAutoScriptLoaderDisabler(nsIDocument* aDoc)
+  explicit nsAutoScriptLoaderDisabler(nsIDocument* aDoc)
   {
     mLoader = aDoc->ScriptLoader();
     mWasEnabled = mLoader->GetEnabled();
     if (mWasEnabled) {
       mLoader->SetEnabled(false);
     }
   }
 

--- a/content/base/src/nsSyncLoadService.cpp
+++ b/content/base/src/nsSyncLoadService.cpp
@@ -63,17 +63,17 @@ private:
     nsresult mAsyncLoadStatus;
 };
 
 class nsForceXMLListener : public nsIStreamListener
 {
     virtual ~nsForceXMLListener();
 
 public:
-    nsForceXMLListener(nsIStreamListener* aListener);
+    explicit nsForceXMLListener(nsIStreamListener* aListener);
 
     NS_DECL_ISUPPORTS
     NS_FORWARD_NSISTREAMLISTENER(mListener->)
     NS_DECL_NSIREQUESTOBSERVER
 
 private:
     nsCOMPtr<nsIStreamListener> mListener;
 };

--- a/content/base/src/nsTextNode.h
+++ b/content/base/src/nsTextNode.h
@@ -26,23 +26,23 @@ class nsTextNode : public mozilla::dom::
 private:
   void Init()
   {
     NS_ABORT_IF_FALSE(mNodeInfo->NodeType() == nsIDOMNode::TEXT_NODE,
                       "Bad NodeType in aNodeInfo");
   }
 
 public:
-  nsTextNode(already_AddRefed<mozilla::dom::NodeInfo>& aNodeInfo)
+  explicit nsTextNode(already_AddRefed<mozilla::dom::NodeInfo>& aNodeInfo)
     : mozilla::dom::Text(aNodeInfo)
   {
     Init();
   }
 
-  nsTextNode(nsNodeInfoManager* aNodeInfoManager)
+  explicit nsTextNode(nsNodeInfoManager* aNodeInfoManager)
     : mozilla::dom::Text(aNodeInfoManager->GetTextNodeInfo())
   {
     Init();
   }
 
   // nsISupports
   NS_DECL_ISUPPORTS_INHERITED
 

--- a/content/base/src/nsXMLHttpRequest.cpp
+++ b/content/base/src/nsXMLHttpRequest.cpp
@@ -144,17 +144,17 @@ using namespace mozilla::dom;
     return NS_OK;                                                               \
   }
 
 NS_IMPL_ISUPPORTS(nsXHRParseEndListener, nsIDOMEventListener)
 
 class nsResumeTimeoutsEvent : public nsRunnable
 {
 public:
-  nsResumeTimeoutsEvent(nsPIDOMWindow* aWindow) : mWindow(aWindow) {}
+  explicit nsResumeTimeoutsEvent(nsPIDOMWindow* aWindow) : mWindow(aWindow) {}
 
   NS_IMETHOD Run()
   {
     mWindow->ResumeTimeouts(false);
     return NS_OK;
   }
 
 private:
@@ -3410,17 +3410,17 @@ nsXMLHttpRequest::ChangeState(uint32_t a
 
 /*
  * Simple helper class that just forwards the redirect callback back
  * to the nsXMLHttpRequest.
  */
 class AsyncVerifyRedirectCallbackForwarder MOZ_FINAL : public nsIAsyncVerifyRedirectCallback
 {
 public:
-  AsyncVerifyRedirectCallbackForwarder(nsXMLHttpRequest *xhr)
+  explicit AsyncVerifyRedirectCallbackForwarder(nsXMLHttpRequest* xhr)
     : mXHR(xhr)
   {
   }
 
   NS_DECL_CYCLE_COLLECTING_ISUPPORTS
   NS_DECL_CYCLE_COLLECTION_CLASS(AsyncVerifyRedirectCallbackForwarder)
 
   // nsIAsyncVerifyRedirectCallback implementation

--- a/content/html/content/public/HTMLAudioElement.h
+++ b/content/html/content/public/HTMLAudioElement.h
@@ -16,17 +16,17 @@ typedef uint16_t nsMediaReadyState;
 namespace mozilla {
 namespace dom {
 
 class HTMLAudioElement MOZ_FINAL : public HTMLMediaElement
 {
 public:
   typedef mozilla::dom::NodeInfo NodeInfo;
 
-  HTMLAudioElement(already_AddRefed<NodeInfo>& aNodeInfo);
+  explicit HTMLAudioElement(already_AddRefed<NodeInfo>& aNodeInfo);
 
   // nsIDOMHTMLMediaElement
   using HTMLMediaElement::GetPaused;
 
   virtual nsresult Clone(NodeInfo *aNodeInfo, nsINode **aResult) const MOZ_OVERRIDE;
   virtual nsresult SetAcceptHeader(nsIHttpChannel* aChannel) MOZ_OVERRIDE;
 
   virtual nsIDOMNode* AsDOMNode() MOZ_OVERRIDE { return this; }

--- a/content/html/content/public/HTMLMediaElement.h
+++ b/content/html/content/public/HTMLMediaElement.h
@@ -93,17 +93,17 @@ public:
   typedef mozilla::MediaResource MediaResource;
   typedef mozilla::MediaDecoderOwner MediaDecoderOwner;
   typedef mozilla::MetadataTags MetadataTags;
 
   CORSMode GetCORSMode() {
     return mCORSMode;
   }
 
-  HTMLMediaElement(already_AddRefed<mozilla::dom::NodeInfo>& aNodeInfo);
+  explicit HTMLMediaElement(already_AddRefed<mozilla::dom::NodeInfo>& aNodeInfo);
 
   /**
    * This is used when the browser is constructing a video element to play
    * a channel that we've already started loading. The src attribute and
    * <source> children are ignored.
    * @param aChannel the channel to use
    * @param aListener returns a stream listener that should receive
    * notifications for the stream
@@ -612,17 +612,17 @@ protected:
   class MediaLoadListener;
   class StreamListener;
 
   virtual void GetItemValueText(nsAString& text) MOZ_OVERRIDE;
   virtual void SetItemValueText(const nsAString& text) MOZ_OVERRIDE;
 
   class WakeLockBoolWrapper {
   public:
-    WakeLockBoolWrapper(bool val = false)
+    explicit WakeLockBoolWrapper(bool val = false)
       : mValue(val), mCanPlay(true), mOuter(nullptr) {}
 
     ~WakeLockBoolWrapper();
 
     void SetOuter(HTMLMediaElement* outer) { mOuter = outer; }
     void SetCanPlay(bool aCanPlay);
 
     operator bool() const { return mValue; }

--- a/content/html/content/public/HTMLVideoElement.h
+++ b/content/html/content/public/HTMLVideoElement.h
@@ -16,17 +16,17 @@ namespace dom {
 class WakeLock;
 class VideoPlaybackQuality;
 
 class HTMLVideoElement MOZ_FINAL : public HTMLMediaElement
 {
 public:
   typedef mozilla::dom::NodeInfo NodeInfo;
 
-  HTMLVideoElement(already_AddRefed<NodeInfo>& aNodeInfo);
+  explicit HTMLVideoElement(already_AddRefed<NodeInfo>& aNodeInfo);
 
   NS_IMPL_FROMCONTENT_HTML_WITH_TAG(HTMLVideoElement, video)
 
   using HTMLMediaElement::GetPaused;
 
   NS_IMETHOD_(bool) IsVideo() MOZ_OVERRIDE {
     return true;
   }

--- a/content/html/content/src/HTMLAnchorElement.h
+++ b/content/html/content/src/HTMLAnchorElement.h
@@ -21,17 +21,17 @@ namespace dom {
 class HTMLAnchorElement MOZ_FINAL : public nsGenericHTMLElement,
                                     public nsIDOMHTMLAnchorElement,
                                     public Link
 {
 public:
   using Element::GetText;
   using Element::SetText;
 
-  HTMLAnchorElement(already_AddRefed<mozilla::dom::NodeInfo>& aNodeInfo)
+  explicit HTMLAnchorElement(already_AddRefed<mozilla::dom::NodeInfo>& aNodeInfo)
     : nsGenericHTMLElement(aNodeInfo)
     , Link(MOZ_THIS_IN_INITIALIZER_LIST())
   {
   }
 
   // nsISupports
   NS_DECL_ISUPPORTS_INHERITED
 

--- a/content/html/content/src/HTMLAreaElement.h
+++ b/content/html/content/src/HTMLAreaElement.h
@@ -22,17 +22,17 @@ class EventChainPostVisitor;
 class EventChainPreVisitor;
 namespace dom {
 
 class HTMLAreaElement MOZ_FINAL : public nsGenericHTMLElement,
                                   public nsIDOMHTMLAreaElement,
                                   public Link
 {
 public:
-  HTMLAreaElement(already_AddRefed<mozilla::dom::NodeInfo>& aNodeInfo);
+  explicit HTMLAreaElement(already_AddRefed<mozilla::dom::NodeInfo>& aNodeInfo);
 
   // nsISupports
   NS_DECL_ISUPPORTS_INHERITED
 
   // CC
   NS_DECL_CYCLE_COLLECTION_CLASS_INHERITED(HTMLAreaElement,
                                            nsGenericHTMLElement)
 

--- a/content/html/content/src/HTMLBRElement.h
+++ b/content/html/content/src/HTMLBRElement.h
@@ -13,17 +13,17 @@
 
 namespace mozilla {
 namespace dom {
 
 class HTMLBRElement MOZ_FINAL : public nsGenericHTMLElement,
                                 public nsIDOMHTMLBRElement
 {
 public:
-  HTMLBRElement(already_AddRefed<mozilla::dom::NodeInfo>& aNodeInfo);
+  explicit HTMLBRElement(already_AddRefed<mozilla::dom::NodeInfo>& aNodeInfo);
 
   // nsISupports
   NS_DECL_ISUPPORTS_INHERITED
 
   // nsIDOMHTMLBRElement
   NS_DECL_NSIDOMHTMLBRELEMENT
 
   virtual bool ParseAttribute(int32_t aNamespaceID,

--- a/content/html/content/src/HTMLBodyElement.h
+++ b/content/html/content/src/HTMLBodyElement.h
@@ -16,17 +16,17 @@ namespace dom {
 class OnBeforeUnloadEventHandlerNonNull;
 class HTMLBodyElement;
 
 class BodyRule: public nsIStyleRule
 {
   virtual ~BodyRule();
 
 public:
-  BodyRule(HTMLBodyElement* aPart);
+  explicit BodyRule(HTMLBodyElement* aPart);
 
   NS_DECL_ISUPPORTS
 
   // nsIStyleRule interface
   virtual void MapRuleInfoInto(nsRuleData* aRuleData) MOZ_OVERRIDE;
 #ifdef DEBUG
   virtual void List(FILE* out = stdout, int32_t aIndent = 0) const MOZ_OVERRIDE;
 #endif
@@ -36,17 +36,17 @@ public:
 
 class HTMLBodyElement MOZ_FINAL : public nsGenericHTMLElement,
                                   public nsIDOMHTMLBodyElement
 {
 public:
   using Element::GetText;
   using Element::SetText;
 
-  HTMLBodyElement(already_AddRefed<mozilla::dom::NodeInfo>& aNodeInfo)
+  explicit HTMLBodyElement(already_AddRefed<mozilla::dom::NodeInfo>& aNodeInfo)
     : nsGenericHTMLElement(aNodeInfo)
   {
   }
 
   // nsISupports
   NS_DECL_ISUPPORTS_INHERITED
 
   // nsIDOMHTMLBodyElement

--- a/content/html/content/src/HTMLButtonElement.h
+++ b/content/html/content/src/HTMLButtonElement.h
@@ -18,18 +18,18 @@ namespace dom {
 
 class HTMLButtonElement MOZ_FINAL : public nsGenericHTMLFormElementWithState,
                                     public nsIDOMHTMLButtonElement,
                                     public nsIConstraintValidation
 {
 public:
   using nsIConstraintValidation::GetValidationMessage;
 
-  HTMLButtonElement(already_AddRefed<mozilla::dom::NodeInfo>& aNodeInfo,
-                      FromParser aFromParser = NOT_FROM_PARSER);
+  explicit HTMLButtonElement(already_AddRefed<mozilla::dom::NodeInfo>& aNodeInfo,
+                             FromParser aFromParser = NOT_FROM_PARSER);
 
   NS_DECL_CYCLE_COLLECTION_CLASS_INHERITED(HTMLButtonElement,
                                            nsGenericHTMLFormElementWithState)
 
   // nsISupports
   NS_DECL_ISUPPORTS_INHERITED
 
   virtual int32_t TabIndexDefault() MOZ_OVERRIDE;

--- a/content/html/content/src/HTMLContentElement.h
+++ b/content/html/content/src/HTMLContentElement.h
@@ -14,17 +14,17 @@ struct nsCSSSelectorList;
 namespace mozilla {
 namespace dom {
 
 class DistributedContentList;
 
 class HTMLContentElement MOZ_FINAL : public nsGenericHTMLElement
 {
 public:
-  HTMLContentElement(already_AddRefed<mozilla::dom::NodeInfo>& aNodeInfo);
+  explicit HTMLContentElement(already_AddRefed<mozilla::dom::NodeInfo>& aNodeInfo);
 
   NS_IMPL_FROMCONTENT_HTML_WITH_TAG(HTMLContentElement, content)
 
   // nsISupports
   NS_DECL_ISUPPORTS_INHERITED
 
   NS_DECL_CYCLE_COLLECTION_CLASS_INHERITED(HTMLContentElement,
                                            nsGenericHTMLElement)
@@ -93,17 +93,17 @@ protected:
   nsAutoPtr<nsCSSSelectorList> mSelectorList;
   bool mValidSelector;
   bool mIsInsertionPoint;
 };
 
 class DistributedContentList : public nsINodeList
 {
 public:
-  DistributedContentList(HTMLContentElement* aHostElement);
+  explicit DistributedContentList(HTMLContentElement* aHostElement);
 
   NS_DECL_CYCLE_COLLECTING_ISUPPORTS
   NS_DECL_CYCLE_COLLECTION_CLASS(DistributedContentList)
 
   // nsIDOMNodeList
   NS_DECL_NSIDOMNODELIST
 
   // nsINodeList

--- a/content/html/content/src/HTMLDataElement.h
+++ b/content/html/content/src/HTMLDataElement.h
@@ -12,17 +12,17 @@
 #include "nsGkAtoms.h"
 
 namespace mozilla {
 namespace dom {
 
 class HTMLDataElement MOZ_FINAL : public nsGenericHTMLElement
 {
 public:
-  HTMLDataElement(already_AddRefed<mozilla::dom::NodeInfo>& aNodeInfo);
+  explicit HTMLDataElement(already_AddRefed<mozilla::dom::NodeInfo>& aNodeInfo);
 
   // HTMLDataElement WebIDL
   void GetValue(nsAString& aValue)
   {
     GetHTMLAttr(nsGkAtoms::value, aValue);
   }
 
   void SetValue(const nsAString& aValue, ErrorResult& aError)

--- a/content/html/content/src/HTMLDataListElement.h
+++ b/content/html/content/src/HTMLDataListElement.h
@@ -10,17 +10,17 @@
 #include "nsContentList.h"
 
 namespace mozilla {
 namespace dom {
 
 class HTMLDataListElement MOZ_FINAL : public nsGenericHTMLElement
 {
 public:
-  HTMLDataListElement(already_AddRefed<mozilla::dom::NodeInfo>& aNodeInfo)
+  explicit HTMLDataListElement(already_AddRefed<mozilla::dom::NodeInfo>& aNodeInfo)
     : nsGenericHTMLElement(aNodeInfo)
   {
   }
 
   // nsISupports
   NS_DECL_ISUPPORTS_INHERITED
 
   nsContentList* Options()

--- a/content/html/content/src/HTMLDivElement.h
+++ b/content/html/content/src/HTMLDivElement.h
@@ -11,17 +11,17 @@
 
 namespace mozilla {
 namespace dom {
 
 class HTMLDivElement MOZ_FINAL : public nsGenericHTMLElement,
                                  public nsIDOMHTMLDivElement
 {
 public:
-  HTMLDivElement(already_AddRefed<mozilla::dom::NodeInfo>& aNodeInfo)
+  explicit HTMLDivElement(already_AddRefed<mozilla::dom::NodeInfo>& aNodeInfo)
     : nsGenericHTMLElement(aNodeInfo)
   {
   }
 
   // nsISupports
   NS_DECL_ISUPPORTS_INHERITED
 
   // nsIDOMHTMLDivElement

--- a/content/html/content/src/HTMLElement.cpp
+++ b/content/html/content/src/HTMLElement.cpp
@@ -8,17 +8,17 @@
 #include "nsContentUtils.h"
 
 namespace mozilla {
 namespace dom {
 
 class HTMLElement MOZ_FINAL : public nsGenericHTMLElement
 {
 public:
-  HTMLElement(already_AddRefed<mozilla::dom::NodeInfo>& aNodeInfo);
+  explicit HTMLElement(already_AddRefed<mozilla::dom::NodeInfo>& aNodeInfo);
   virtual ~HTMLElement();
 
   NS_IMETHOD GetInnerHTML(nsAString& aInnerHTML) MOZ_OVERRIDE;
 
   virtual nsresult Clone(mozilla::dom::NodeInfo* aNodeInfo,
                          nsINode** aResult) const MOZ_OVERRIDE;
 
 protected:

--- a/content/html/content/src/HTMLFieldSetElement.h
+++ b/content/html/content/src/HTMLFieldSetElement.h
@@ -22,17 +22,17 @@ class HTMLFieldSetElement MOZ_FINAL : pu
                                       public nsIConstraintValidation
 {
 public:
   using nsGenericHTMLFormElement::GetForm;
   using nsIConstraintValidation::Validity;
   using nsIConstraintValidation::CheckValidity;
   using nsIConstraintValidation::GetValidationMessage;
 
-  HTMLFieldSetElement(already_AddRefed<mozilla::dom::NodeInfo>& aNodeInfo);
+  explicit HTMLFieldSetElement(already_AddRefed<mozilla::dom::NodeInfo>& aNodeInfo);
 
   NS_IMPL_FROMCONTENT_HTML_WITH_TAG(HTMLFieldSetElement, fieldset)
 
   // nsISupports
   NS_DECL_ISUPPORTS_INHERITED
 
   // nsIDOMHTMLFieldSetElement
   NS_DECL_NSIDOMHTMLFIELDSETELEMENT

--- a/content/html/content/src/HTMLFontElement.h
+++ b/content/html/content/src/HTMLFontElement.h
@@ -9,17 +9,17 @@
 #include "nsGenericHTMLElement.h"
 
 namespace mozilla {
 namespace dom {
 
 class HTMLFontElement MOZ_FINAL : public nsGenericHTMLElement
 {
 public:
-  HTMLFontElement(already_AddRefed<mozilla::dom::NodeInfo>& aNodeInfo)
+  explicit HTMLFontElement(already_AddRefed<mozilla::dom::NodeInfo>& aNodeInfo)
     : nsGenericHTMLElement(aNodeInfo)
   {
   }
 
   void GetColor(nsString& aColor)
   {
     GetHTMLAttr(nsGkAtoms::color, aColor);
   }

--- a/content/html/content/src/HTMLFormControlsCollection.h
+++ b/content/html/content/src/HTMLFormControlsCollection.h
@@ -22,17 +22,17 @@ class HTMLFormElement;
 class HTMLImageElement;
 class OwningRadioNodeListOrElement;
 template<typename> struct Nullable;
 
 class HTMLFormControlsCollection : public nsIHTMLCollection
                                  , public nsWrapperCache
 {
 public:
-  HTMLFormControlsCollection(HTMLFormElement* aForm);
+  explicit HTMLFormControlsCollection(HTMLFormElement* aForm);
 
   void DropFormReference();
 
   NS_DECL_CYCLE_COLLECTING_ISUPPORTS
 
   // nsIDOMHTMLCollection interface
   NS_DECL_NSIDOMHTMLCOLLECTION
 

--- a/content/html/content/src/HTMLFormElement.h
+++ b/content/html/content/src/HTMLFormElement.h
@@ -37,17 +37,17 @@ class HTMLFormElement MOZ_FINAL : public
                                   public nsIDOMHTMLFormElement,
                                   public nsIWebProgressListener,
                                   public nsIForm,
                                   public nsIRadioGroupContainer
 {
   friend class HTMLFormControlsCollection;
 
 public:
-  HTMLFormElement(already_AddRefed<mozilla::dom::NodeInfo>& aNodeInfo);
+  explicit HTMLFormElement(already_AddRefed<mozilla::dom::NodeInfo>& aNodeInfo);
 
   enum {
     FORM_CONTROL_LIST_HASHTABLE_LENGTH = 8
   };
 
   // nsISupports
   NS_DECL_ISUPPORTS_INHERITED
 
@@ -432,17 +432,17 @@ protected:
 
   nsRefPtr<FormPasswordEventDispatcher> mFormPasswordEventDispatcher;
 
   class RemoveElementRunnable;
   friend class RemoveElementRunnable;
 
   class RemoveElementRunnable : public nsRunnable {
   public:
-    RemoveElementRunnable(HTMLFormElement* aForm)
+    explicit RemoveElementRunnable(HTMLFormElement* aForm)
       : mForm(aForm)
     {}
 
     NS_IMETHOD Run() MOZ_OVERRIDE {
       mForm->HandleDefaultSubmitRemoval();
       return NS_OK;
     }
 

--- a/content/html/content/src/HTMLFrameElement.h
+++ b/content/html/content/src/HTMLFrameElement.h
@@ -17,18 +17,18 @@ namespace mozilla {
 namespace dom {
 
 class HTMLFrameElement MOZ_FINAL : public nsGenericHTMLFrameElement,
                                    public nsIDOMHTMLFrameElement
 {
 public:
   using nsGenericHTMLFrameElement::SwapFrameLoaders;
 
-  HTMLFrameElement(already_AddRefed<mozilla::dom::NodeInfo>& aNodeInfo,
-                   FromParser aFromParser = NOT_FROM_PARSER);
+  explicit HTMLFrameElement(already_AddRefed<mozilla::dom::NodeInfo>& aNodeInfo,
+                            FromParser aFromParser = NOT_FROM_PARSER);
 
   // nsISupports
   NS_DECL_ISUPPORTS_INHERITED
 
   // nsIDOMHTMLFrameElement
   NS_DECL_NSIDOMHTMLFRAMEELEMENT
 
   // nsIContent

--- a/content/html/content/src/HTMLFrameSetElement.h
+++ b/content/html/content/src/HTMLFrameSetElement.h
@@ -41,17 +41,17 @@ namespace mozilla {
 namespace dom {
 
 class OnBeforeUnloadEventHandlerNonNull;
 
 class HTMLFrameSetElement MOZ_FINAL : public nsGenericHTMLElement,
                                       public nsIDOMHTMLFrameSetElement
 {
 public:
-  HTMLFrameSetElement(already_AddRefed<mozilla::dom::NodeInfo>& aNodeInfo)
+  explicit HTMLFrameSetElement(already_AddRefed<mozilla::dom::NodeInfo>& aNodeInfo)
     : nsGenericHTMLElement(aNodeInfo),
       mNumRows(0),
       mNumCols(0),
       mCurrentRowColHint(NS_STYLE_HINT_REFLOW)
   {
     SetHasWeirdParserInsertionMode();
   }
 

--- a/content/html/content/src/HTMLHRElement.h
+++ b/content/html/content/src/HTMLHRElement.h
@@ -15,17 +15,17 @@
 
 namespace mozilla {
 namespace dom {
 
 class HTMLHRElement MOZ_FINAL : public nsGenericHTMLElement,
                                 public nsIDOMHTMLHRElement
 {
 public:
-  HTMLHRElement(already_AddRefed<mozilla::dom::NodeInfo>& aNodeInfo);
+  explicit HTMLHRElement(already_AddRefed<mozilla::dom::NodeInfo>& aNodeInfo);
 
   // nsISupports
   NS_DECL_ISUPPORTS_INHERITED
 
   // nsIDOMHTMLHRElement
   NS_DECL_NSIDOMHTMLHRELEMENT
 
   virtual bool ParseAttribute(int32_t aNamespaceID,

--- a/content/html/content/src/HTMLHeadingElement.h
+++ b/content/html/content/src/HTMLHeadingElement.h
@@ -12,17 +12,17 @@
 
 namespace mozilla {
 namespace dom {
 
 class HTMLHeadingElement MOZ_FINAL : public nsGenericHTMLElement,
 				     public nsIDOMHTMLHeadingElement
 {
 public:
-  HTMLHeadingElement(already_AddRefed<mozilla::dom::NodeInfo>& aNodeInfo)
+  explicit HTMLHeadingElement(already_AddRefed<mozilla::dom::NodeInfo>& aNodeInfo)
     : nsGenericHTMLElement(aNodeInfo)
   {
   }
 
   // nsISupports
   NS_DECL_ISUPPORTS_INHERITED
 
   // nsIDOMHTMLHeadingElement

--- a/content/html/content/src/HTMLIFrameElement.h
+++ b/content/html/content/src/HTMLIFrameElement.h
@@ -13,18 +13,18 @@
 
 namespace mozilla {
 namespace dom {
 
 class HTMLIFrameElement MOZ_FINAL : public nsGenericHTMLFrameElement
                                   , public nsIDOMHTMLIFrameElement
 {
 public:
-  HTMLIFrameElement(already_AddRefed<mozilla::dom::NodeInfo>& aNodeInfo,
-                    FromParser aFromParser = NOT_FROM_PARSER);
+  explicit HTMLIFrameElement(already_AddRefed<mozilla::dom::NodeInfo>& aNodeInfo,
+                             FromParser aFromParser = NOT_FROM_PARSER);
 
   NS_IMPL_FROMCONTENT_HTML_WITH_TAG(HTMLIFrameElement, iframe)
 
   // nsISupports
   NS_DECL_ISUPPORTS_INHERITED
 
   // nsIDOMHTMLIFrameElement
   NS_DECL_NSIDOMHTMLIFRAMEELEMENT

--- a/content/html/content/src/HTMLInputElement.cpp
+++ b/content/html/content/src/HTMLInputElement.cpp
@@ -332,17 +332,17 @@ namespace {
 class DirPickerRecursiveFileEnumerator MOZ_FINAL
   : public nsISimpleEnumerator
 {
   ~DirPickerRecursiveFileEnumerator() {}
 
 public:
   NS_DECL_ISUPPORTS
 
-  DirPickerRecursiveFileEnumerator(nsIFile* aTopDir)
+  explicit DirPickerRecursiveFileEnumerator(nsIFile* aTopDir)
     : mTopDir(aTopDir)
   {
     MOZ_ASSERT(!NS_IsMainThread(), "This class blocks on I/O!");
 
 #ifdef DEBUG
     {
       bool isDir;
       aTopDir->IsDirectory(&isDir);

--- a/content/html/content/src/HTMLInputElement.h
+++ b/content/html/content/src/HTMLInputElement.h
@@ -1352,17 +1352,17 @@ private:
            aType == NS_FORM_INPUT_RANGE ||
            aType == NS_FORM_INPUT_NUMBER;
   }
 
   struct nsFilePickerFilter {
     nsFilePickerFilter()
       : mFilterMask(0), mIsTrusted(false) {}
 
-    nsFilePickerFilter(int32_t aFilterMask)
+    explicit nsFilePickerFilter(int32_t aFilterMask)
       : mFilterMask(aFilterMask), mIsTrusted(true) {}
 
     nsFilePickerFilter(const nsString& aTitle,
                        const nsString& aFilter,
                        const bool aIsTrusted = false)
       : mFilterMask(0), mTitle(aTitle), mFilter(aFilter), mIsTrusted(aIsTrusted) {}
 
     nsFilePickerFilter(const nsFilePickerFilter& other) {

--- a/content/html/content/src/HTMLLIElement.h
+++ b/content/html/content/src/HTMLLIElement.h
@@ -13,17 +13,17 @@
 
 namespace mozilla {
 namespace dom {
 
 class HTMLLIElement MOZ_FINAL : public nsGenericHTMLElement,
                                 public nsIDOMHTMLLIElement
 {
 public:
-  HTMLLIElement(already_AddRefed<mozilla::dom::NodeInfo>& aNodeInfo)
+  explicit HTMLLIElement(already_AddRefed<mozilla::dom::NodeInfo>& aNodeInfo)
     : nsGenericHTMLElement(aNodeInfo)
   {
   }
 
   // nsISupports
   NS_DECL_ISUPPORTS_INHERITED
 
   // nsIDOMHTMLLIElement

--- a/content/html/content/src/HTMLLabelElement.h
+++ b/content/html/content/src/HTMLLabelElement.h
@@ -16,17 +16,17 @@
 namespace mozilla {
 class EventChainPostVisitor;
 namespace dom {
 
 class HTMLLabelElement MOZ_FINAL : public nsGenericHTMLFormElement,
                                    public nsIDOMHTMLLabelElement
 {
 public:
-  HTMLLabelElement(already_AddRefed<mozilla::dom::NodeInfo>& aNodeInfo)
+  explicit HTMLLabelElement(already_AddRefed<mozilla::dom::NodeInfo>& aNodeInfo)
     : nsGenericHTMLFormElement(aNodeInfo),
       mHandlingEvent(false)
   {
   }
 
   NS_IMPL_FROMCONTENT_HTML_WITH_TAG(HTMLLabelElement, label)
 
   // nsISupports

--- a/content/html/content/src/HTMLLegendElement.h
+++ b/content/html/content/src/HTMLLegendElement.h
@@ -11,17 +11,17 @@
 #include "mozilla/dom/HTMLFormElement.h"
 
 namespace mozilla {
 namespace dom {
 
 class HTMLLegendElement MOZ_FINAL : public nsGenericHTMLElement
 {
 public:
-  HTMLLegendElement(already_AddRefed<mozilla::dom::NodeInfo>& aNodeInfo)
+  explicit HTMLLegendElement(already_AddRefed<mozilla::dom::NodeInfo>& aNodeInfo)
     : nsGenericHTMLElement(aNodeInfo)
   {
   }
 
   NS_IMPL_FROMCONTENT_HTML_WITH_TAG(HTMLLegendElement, legend)
 
   using nsGenericHTMLElement::Focus;
   virtual void Focus(ErrorResult& aError) MOZ_OVERRIDE;

--- a/content/html/content/src/HTMLLinkElement.h
+++ b/content/html/content/src/HTMLLinkElement.h
@@ -19,17 +19,17 @@ class EventChainPreVisitor;
 namespace dom {
 
 class HTMLLinkElement MOZ_FINAL : public nsGenericHTMLElement,
                                   public nsIDOMHTMLLinkElement,
                                   public nsStyleLinkElement,
                                   public Link
 {
 public:
-  HTMLLinkElement(already_AddRefed<mozilla::dom::NodeInfo>& aNodeInfo);
+  explicit HTMLLinkElement(already_AddRefed<mozilla::dom::NodeInfo>& aNodeInfo);
 
   // nsISupports
   NS_DECL_ISUPPORTS_INHERITED
 
   // CC
   NS_DECL_CYCLE_COLLECTION_CLASS_INHERITED(HTMLLinkElement,
                                            nsGenericHTMLElement)
 

--- a/content/html/content/src/HTMLMapElement.h
+++ b/content/html/content/src/HTMLMapElement.h
@@ -16,17 +16,17 @@ class nsContentList;
 
 namespace mozilla {
 namespace dom {
 
 class HTMLMapElement MOZ_FINAL : public nsGenericHTMLElement,
                                  public nsIDOMHTMLMapElement
 {
 public:
-  HTMLMapElement(already_AddRefed<mozilla::dom::NodeInfo>& aNodeInfo);
+  explicit HTMLMapElement(already_AddRefed<mozilla::dom::NodeInfo>& aNodeInfo);
 
   // nsISupports
   NS_DECL_ISUPPORTS_INHERITED
 
   // nsIDOMHTMLMapElement
   NS_DECL_NSIDOMHTMLMAPELEMENT
 
   virtual nsresult Clone(mozilla::dom::NodeInfo *aNodeInfo, nsINode **aResult) const MOZ_OVERRIDE;

--- a/content/html/content/src/HTMLMediaElement.cpp
+++ b/content/html/content/src/HTMLMediaElement.cpp
@@ -168,17 +168,17 @@ static const double THRESHOLD_LOW_PLAYBA
 // garbage collected while there are still event listeners that should
 // receive events. If we neglect to remove the self-reference then the element
 // just lives longer than it needs to.
 
 class nsMediaEvent : public nsRunnable
 {
 public:
 
-  nsMediaEvent(HTMLMediaElement* aElement) :
+  explicit nsMediaEvent(HTMLMediaElement* aElement) :
     mElement(aElement),
     mLoadID(mElement->GetCurrentLoadID()) {}
   ~nsMediaEvent() {}
 
   NS_IMETHOD Run() = 0;
 
 protected:
   bool IsCancelled() {
@@ -251,17 +251,17 @@ class HTMLMediaElement::MediaLoadListene
   NS_DECL_ISUPPORTS
   NS_DECL_NSIREQUESTOBSERVER
   NS_DECL_NSISTREAMLISTENER
   NS_DECL_NSICHANNELEVENTSINK
   NS_DECL_NSIOBSERVER
   NS_DECL_NSIINTERFACEREQUESTOR
 
 public:
-  MediaLoadListener(HTMLMediaElement* aElement)
+  explicit MediaLoadListener(HTMLMediaElement* aElement)
     : mElement(aElement),
       mLoadID(aElement->GetCurrentLoadID())
   {
     NS_ABORT_IF_FALSE(mElement, "Must pass an element to call back");
   }
 
 private:
   nsRefPtr<HTMLMediaElement> mElement;
@@ -1899,17 +1899,17 @@ NS_IMETHODIMP HTMLMediaElement::MozCaptu
 NS_IMETHODIMP HTMLMediaElement::GetMozAudioCaptured(bool* aCaptured)
 {
   *aCaptured = MozAudioCaptured();
   return NS_OK;
 }
 
 class MediaElementSetForURI : public nsURIHashKey {
 public:
-  MediaElementSetForURI(const nsIURI* aKey) : nsURIHashKey(aKey) {}
+  explicit MediaElementSetForURI(const nsIURI* aKey) : nsURIHashKey(aKey) {}
   MediaElementSetForURI(const MediaElementSetForURI& toCopy)
     : nsURIHashKey(toCopy), mElements(toCopy.mElements) {}
   nsTArray<HTMLMediaElement*> mElements;
 };
 
 typedef nsTHashtable<MediaElementSetForURI> MediaElementURITable;
 // Elements in this table must have non-null mDecoder and mLoadingSrc, and those
 // can't change while the element is in the table. The table is keyed by
@@ -2703,17 +2703,17 @@ nsresult HTMLMediaElement::FinishDecoder
     "Media element should have single table entry if decode initialized");
 
   mBegun = true;
   return rv;
 }
 
 class HTMLMediaElement::StreamListener : public MediaStreamListener {
 public:
-  StreamListener(HTMLMediaElement* aElement) :
+  explicit StreamListener(HTMLMediaElement* aElement) :
     mElement(aElement),
     mHaveCurrentData(false),
     mBlocked(false),
     mMutex("HTMLMediaElement::StreamListener"),
     mPendingNotifyOutput(false)
   {}
   void Forget() { mElement = nullptr; }