Bug 1073336 part 1 - Move CheckNeedsRefreshes to CommonAnimationManager; r=dbaron

In order to add AnimationPlayerCollection::NotifyPlayerUpdated, collections
need a way of updating their managers to inform them that their mNeedsRefreshes
flag has changed and hence the manager may need to resume observing the refresh
driver.

Currently, only nsAnimationManager makes use of mNeedsRefreshes and provides
a CheckNeedsRefresh method. In order to allow AnimationPlayerCollection to
operate independently of the type of manager it is attached to (and because
there's a lot of similar code here that we eventually want to move to a common
manager anyway), this patch moves CheckNeedsRefreshes and associated
machinery to CommonAnimationManager.

layout/style/AnimationCommon.cpp

@@ -52,6 +52,7 @@ namespace css {
 
 CommonAnimationManager::CommonAnimationManager(nsPresContext *aPresContext)
   : mPresContext(aPresContext)
+  , mIsObservingRefreshDriver(false)
 {
   PR_INIT_CLIST(&mElementCollections);
 }
@@ -70,6 +71,21 @@ CommonAnimationManager::Disconnect()
   mPresContext = nullptr;
 }
 
+void
+CommonAnimationManager::AddElementCollection(AnimationPlayerCollection*
+                                               aCollection)
+{
+  if (!mIsObservingRefreshDriver) {
+    NS_ASSERTION(aCollection->mNeedsRefreshes,
+      "Added data which doesn't need refreshing?");
+    // We need to observe the refresh driver.
+    mPresContext->RefreshDriver()->AddRefreshObserver(this, Flush_Style);
+    mIsObservingRefreshDriver = true;
+  }
+
+  PR_INSERT_BEFORE(aCollection, &mElementCollections);
+}
+
 void
 CommonAnimationManager::RemoveAllElementCollections()
 {
@@ -81,6 +97,26 @@ CommonAnimationManager::RemoveAllElementCollections()
   }
 }
 
+void
+CommonAnimationManager::CheckNeedsRefresh()
+{
+  for (PRCList *l = PR_LIST_HEAD(&mElementCollections);
+       l != &mElementCollections;
+       l = PR_NEXT_LINK(l)) {
+    if (static_cast<AnimationPlayerCollection*>(l)->mNeedsRefreshes) {
+      if (!mIsObservingRefreshDriver) {
+        mPresContext->RefreshDriver()->AddRefreshObserver(this, Flush_Style);
+        mIsObservingRefreshDriver = true;
+      }
+      return;
+    }
+  }
+  if (mIsObservingRefreshDriver) {
+    mIsObservingRefreshDriver = false;
+    mPresContext->RefreshDriver()->RemoveRefreshObserver(this, Flush_Style);
+  }
+}
+
 AnimationPlayerCollection*
 CommonAnimationManager::GetAnimationsForCompositor(nsIContent* aContent,
                                                    nsIAtom* aElementProperty,

layout/style/AnimationCommon.h

@@ -75,17 +75,20 @@ public:
                   nsCSSProperty aProperty,
                   nsStyleContext* aStyleContext,
                   mozilla::StyleAnimationValue& aComputedValue);
+
 protected:
   virtual ~CommonAnimationManager();
 
   // For ElementCollectionRemoved
   friend struct mozilla::AnimationPlayerCollection;
 
-  virtual void
-  AddElementCollection(AnimationPlayerCollection* aCollection) = 0;
-  virtual void ElementCollectionRemoved() = 0;
+  void AddElementCollection(AnimationPlayerCollection* aCollection);
+  void ElementCollectionRemoved() { CheckNeedsRefresh(); }
   void RemoveAllElementCollections();
 
+  // Check to see if we should stop or start observing the refresh driver
+  void CheckNeedsRefresh();
+
   // When this returns a value other than nullptr, it also,
   // as a side-effect, notifies the ActiveLayerTracker.
   static AnimationPlayerCollection*
@@ -95,6 +98,7 @@ protected:
 
   PRCList mElementCollections;
   nsPresContext *mPresContext; // weak (non-null from ctor to Disconnect)
+  bool mIsObservingRefreshDriver;
 };
 
 /**
@@ -185,9 +189,8 @@ struct AnimationPlayerCollection : public PRCList
   void Tick();
 
   // This updates mNeedsRefreshes so the caller may need to check
-  // for changes to values (for example, nsAnimationManager provides
-  // CheckNeedsRefresh to register or unregister from observing the refresh
-  // driver when this value changes).
+  // for changes to values (for example, calling CheckNeedsRefresh to register
+  // or unregister from observing the refresh driver when this value changes).
   void EnsureStyleRuleFor(TimeStamp aRefreshTime, EnsureStyleRuleFlags aFlags);
 
   bool CanThrottleTransformChanges(mozilla::TimeStamp aTime);

layout/style/nsAnimationManager.cpp

@@ -760,42 +760,6 @@ nsAnimationManager::WillRefresh(mozilla::TimeStamp aTime)
   FlushAnimations(Can_Throttle);
 }
 
-void
-nsAnimationManager::AddElementCollection(
-  AnimationPlayerCollection* aCollection)
-{
-  if (!mObservingRefreshDriver) {
-    NS_ASSERTION(
-      static_cast<AnimationPlayerCollection*>(aCollection)->mNeedsRefreshes,
-      "Added data which doesn't need refreshing?");
-    // We need to observe the refresh driver.
-    mPresContext->RefreshDriver()->AddRefreshObserver(this, Flush_Style);
-    mObservingRefreshDriver = true;
-  }
-
-  PR_INSERT_BEFORE(aCollection, &mElementCollections);
-}
-
-void
-nsAnimationManager::CheckNeedsRefresh()
-{
-  for (PRCList *l = PR_LIST_HEAD(&mElementCollections);
-       l != &mElementCollections;
-       l = PR_NEXT_LINK(l)) {
-    if (static_cast<AnimationPlayerCollection*>(l)->mNeedsRefreshes) {
-      if (!mObservingRefreshDriver) {
-        mPresContext->RefreshDriver()->AddRefreshObserver(this, Flush_Style);
-        mObservingRefreshDriver = true;
-      }
-      return;
-    }
-  }
-  if (mObservingRefreshDriver) {
-    mObservingRefreshDriver = false;
-    mPresContext->RefreshDriver()->RemoveRefreshObserver(this, Flush_Style);
-  }
-}
-
 void
 nsAnimationManager::FlushAnimations(FlushFlags aFlags)
 {

layout/style/nsAnimationManager.h

@@ -147,7 +147,6 @@ class nsAnimationManager MOZ_FINAL
 public:
   explicit nsAnimationManager(nsPresContext *aPresContext)
     : mozilla::css::CommonAnimationManager(aPresContext)
-    , mObservingRefreshDriver(false)
   {
   }
 
@@ -227,19 +226,6 @@ public:
   nsIStyleRule* GetAnimationRule(mozilla::dom::Element* aElement,
                                  nsCSSPseudoElements::Type aPseudoType);
 
-protected:
-  virtual void ElementCollectionRemoved() MOZ_OVERRIDE
-  {
-    CheckNeedsRefresh();
-  }
-  virtual void
-  AddElementCollection(mozilla::AnimationPlayerCollection* aData) MOZ_OVERRIDE;
-
-  /**
-   * Check to see if we should stop or start observing the refresh driver
-   */
-  void CheckNeedsRefresh();
-
 private:
   void BuildAnimations(nsStyleContext* aStyleContext,
                        mozilla::dom::Element* aTarget,
@@ -257,8 +243,6 @@ private:
   void DoDispatchEvents();
 
   mozilla::EventArray mPendingEvents;
-
-  bool mObservingRefreshDriver;
 };
 
 #endif /* !defined(nsAnimationManager_h_) */

layout/style/nsTransitionManager.cpp

@@ -74,29 +74,6 @@ ElementPropertyTransition::CurrentValuePortion() const
  * nsTransitionManager                                                       *
  *****************************************************************************/
 
-void
-nsTransitionManager::ElementCollectionRemoved()
-{
-  // If we have no transitions or animations left, remove ourselves from
-  // the refresh driver.
-  if (PR_CLIST_IS_EMPTY(&mElementCollections)) {
-    mPresContext->RefreshDriver()->RemoveRefreshObserver(this, Flush_Style);
-  }
-}
-
-void
-nsTransitionManager::AddElementCollection(
-  AnimationPlayerCollection* aCollection)
-{
-  if (PR_CLIST_IS_EMPTY(&mElementCollections)) {
-    // We need to observe the refresh driver.
-    nsRefreshDriver *rd = mPresContext->RefreshDriver();
-    rd->AddRefreshObserver(this, Flush_Style);
-  }
-
-  PR_INSERT_BEFORE(aCollection, &mElementCollections);
-}
-
 already_AddRefed<nsIStyleRule>
 nsTransitionManager::StyleContextChanged(dom::Element *aElement,
                                          nsStyleContext *aOldStyleContext,

layout/style/nsTransitionManager.h

@@ -152,11 +152,6 @@ public:
                           nsCSSPseudoElements::Type aPseudoType,
                           nsRuleWalker* aRuleWalker);
 
-protected:
-  virtual void ElementCollectionRemoved() MOZ_OVERRIDE;
-  virtual void
-  AddElementCollection(AnimationPlayerCollection* aCollection) MOZ_OVERRIDE;
-
 private:
   void
   ConsiderStartingTransition(nsCSSProperty aProperty,