Bug 810179 part.2 EventStateManager should include IMEContentObserver into cycle collector r=smaug

dom/events/EventStateManager.cpp

@@ -20,6 +20,7 @@
 #include "mozilla/dom/UIEvent.h"
 
 #include "ContentEventHandler.h"
+#include "IMEContentObserver.h"
 #include "WheelHandlingHelper.h"
 
 #include "nsCOMPtr.h"
@@ -337,6 +338,8 @@ EventStateManager::Init()
 
 EventStateManager::~EventStateManager()
 {
+  ReleaseCurrentIMEContentObserver();
+
   if (sActiveESM == this) {
     sActiveESM = nullptr;
   }
@@ -410,7 +413,7 @@ NS_INTERFACE_MAP_END
 NS_IMPL_CYCLE_COLLECTING_ADDREF(EventStateManager)
 NS_IMPL_CYCLE_COLLECTING_RELEASE(EventStateManager)
 
-NS_IMPL_CYCLE_COLLECTION_16(EventStateManager,
+NS_IMPL_CYCLE_COLLECTION_17(EventStateManager,
                             mCurrentTargetContent,
                             mGestureDownContent,
                             mGestureDownFrameOwner,
@@ -426,8 +429,35 @@ NS_IMPL_CYCLE_COLLECTION_16(EventStateManager,
                             mMouseEnterLeaveHelper,
                             mPointersEnterLeaveHelper,
                             mDocument,
+                            mIMEContentObserver,
                             mAccessKeys)
 
+void
+EventStateManager::ReleaseCurrentIMEContentObserver()
+{
+  if (mIMEContentObserver) {
+    mIMEContentObserver->DisconnectFromEventStateManager();
+  }
+  mIMEContentObserver = nullptr;
+}
+
+void
+EventStateManager::OnStartToObserveContent(
+                     IMEContentObserver* aIMEContentObserver)
+{
+  ReleaseCurrentIMEContentObserver();
+  mIMEContentObserver = aIMEContentObserver;
+}
+
+void
+EventStateManager::OnStopObservingContent(
+                     IMEContentObserver* aIMEContentObserver)
+{
+  aIMEContentObserver->DisconnectFromEventStateManager();
+  NS_ENSURE_TRUE_VOID(mIMEContentObserver == aIMEContentObserver);
+  mIMEContentObserver = nullptr;
+}
+
 nsresult
 EventStateManager::PreHandleEvent(nsPresContext* aPresContext,
                                   WidgetEvent* aEvent,

dom/events/EventStateManager.h

@@ -34,6 +34,7 @@ namespace mozilla {
 
 class EnterLeaveDispatcher;
 class EventStates;
+class IMEContentObserver;
 class ScrollbarsForWheel;
 class WheelTransaction;
 
@@ -133,6 +134,14 @@ public:
   void ContentRemoved(nsIDocument* aDocument, nsIContent* aContent);
   bool EventStatusOK(WidgetGUIEvent* aEvent);
 
+  /**
+   * EventStateManager stores IMEContentObserver while it's observing contents.
+   * Following mehtods are called by IMEContentObserver when it starts to
+   * observe or stops observing the content.
+   */
+  void OnStartToObserveContent(IMEContentObserver* aIMEContentObserver);
+  void OnStopObservingContent(IMEContentObserver* aIMEContentObserver);
+
   /**
    * Register accesskey on the given element. When accesskey is activated then
    * the element will be notified via nsIContent::PerformAccesskey() method.
@@ -777,6 +786,8 @@ protected:
                                nsIFrame* aTargetFrame,
                                nsEventStatus* aStatus);
 
+  void ReleaseCurrentIMEContentObserver();
+
 private:
   static inline void DoStateChange(dom::Element* aElement,
                                    EventStates aState, bool aAddState);
@@ -839,6 +850,8 @@ private:
   nsPresContext* mPresContext;      // Not refcnted
   nsCOMPtr<nsIDocument> mDocument;   // Doesn't necessarily need to be owner
 
+  nsRefPtr<IMEContentObserver> mIMEContentObserver;
+
   uint32_t mLClickCount;
   uint32_t mMClickCount;
   uint32_t mRClickCount;

dom/events/IMEContentObserver.cpp

@@ -7,6 +7,7 @@
 #include "ContentEventHandler.h"
 #include "IMEContentObserver.h"
 #include "mozilla/AsyncEventDispatcher.h"
+#include "mozilla/EventStateManager.h"
 #include "mozilla/IMEStateManager.h"
 #include "mozilla/TextComposition.h"
 #include "mozilla/dom/Element.h"
@@ -50,6 +51,7 @@ NS_IMPL_CYCLE_COLLECTING_ADDREF(IMEContentObserver)
 NS_IMPL_CYCLE_COLLECTING_RELEASE(IMEContentObserver)
 
 IMEContentObserver::IMEContentObserver()
+  : mESM(nullptr)
 {
 }
 
@@ -58,6 +60,9 @@ IMEContentObserver::Init(nsIWidget* aWidget,
                          nsPresContext* aPresContext,
                          nsIContent* aContent)
 {
+  mESM = aPresContext->EventStateManager();
+  mESM->OnStartToObserveContent(this);
+
   mWidget = aWidget;
   mEditableNode = IMEStateManager::GetRootEditableNode(aPresContext, aContent);
   if (!mEditableNode) {
@@ -183,6 +188,17 @@ IMEContentObserver::Destroy()
   mEditableNode = nullptr;
   mDocShell = nullptr;
   mUpdatePreference.mWantUpdates = nsIMEUpdatePreference::NOTIFY_NOTHING;
+
+  if (mESM) {
+    mESM->OnStopObservingContent(this);
+    mESM = nullptr;
+  }
+}
+
+void
+IMEContentObserver::DisconnectFromEventStateManager()
+{
+  mESM = nullptr;
 }
 
 bool

dom/events/IMEContentObserver.h

@@ -25,6 +25,8 @@ class nsPresContext;
 
 namespace mozilla {
 
+class EventStateManager;
+
 // IMEContentObserver notifies widget of any text and selection changes
 // in the currently focused editor
 class IMEContentObserver MOZ_FINAL : public nsISelectionListener,
@@ -54,6 +56,12 @@ public:
   void Init(nsIWidget* aWidget, nsPresContext* aPresContext,
             nsIContent* aContent);
   void Destroy();
+  /**
+   * IMEContentObserver is stored by EventStateManager during observing.
+   * DisconnectFromEventStateManager() is called when EventStateManager stops
+   * storing the instance.
+   */
+  void DisconnectFromEventStateManager();
   bool IsManaging(nsPresContext* aPresContext, nsIContent* aContent);
   bool IsEditorHandlingEventForComposition() const;
   bool KeepAliveDuringDeactive() const
@@ -73,6 +81,9 @@ private:
   nsCOMPtr<nsIContent> mRootContent;
   nsCOMPtr<nsINode> mEditableNode;
   nsCOMPtr<nsIDocShell> mDocShell;
+
+  EventStateManager* mESM;
+
   nsIMEUpdatePreference mUpdatePreference;
   uint32_t mPreAttrChangeLength;
 };