Bug 1448439 - Allow the concrete type of fling animations to be determined dynamically. r=kats

MozReview-Commit-ID: EBscYyxdlwr

--HG--
extra : rebase_source : 19de9aa3c6d1482ace56ce6a4314fe2538a760a7

gfx/layers/apz/src/AndroidAPZ.cpp

@@ -43,6 +43,17 @@ AndroidSpecificState::AndroidSpecificState() {
   mOverScroller = scroller;
 }
 
+AsyncPanZoomAnimation*
+AndroidSpecificState::CreateFlingAnimation(AsyncPanZoomController& aApzc,
+                                           const FlingHandoffState& aHandoffState) {
+  return new AndroidFlingAnimation(aApzc,
+      this,
+      aHandoffState.mChain,
+      aHandoffState.mIsHandoff,
+      aHandoffState.mScrolledApzc);
+}
+
+
 const float BOUNDS_EPSILON = 1.0f;
 
 // This function is used to convert the scroll offset from a float to an integer

gfx/layers/apz/src/AndroidAPZ.h

@@ -22,6 +22,9 @@ public:
     return this;
   }
 
+  virtual AsyncPanZoomAnimation* CreateFlingAnimation(AsyncPanZoomController& aApzc,
+                                                      const FlingHandoffState& aHandoffState) override;
+
   java::StackScroller::GlobalRef mOverScroller;
   TimeStamp mLastFling;
 };

gfx/layers/apz/src/AsyncPanZoomController.cpp

@@ -118,11 +118,9 @@ using mozilla::gfx::PointTyped;
 #ifdef MOZ_WIDGET_ANDROID
 typedef WidgetOverscrollEffect OverscrollEffect;
 typedef AndroidSpecificState PlatformSpecificState;
-typedef AndroidFlingAnimation FlingAnimation;
 #else
 typedef GenericOverscrollEffect OverscrollEffect;
 typedef PlatformSpecificStateBase PlatformSpecificState;  // no extra state, just use the base class
-typedef GenericFlingAnimation FlingAnimation;
 #endif
 
 /**
@@ -516,6 +514,16 @@ static bool IsCloseToVertical(float aAngle, float aThreshold)
 // Counter used to give each APZC a unique id
 static uint32_t sAsyncPanZoomControllerCount = 0;
 
+AsyncPanZoomAnimation*
+PlatformSpecificStateBase::CreateFlingAnimation(AsyncPanZoomController& aApzc,
+                                                const FlingHandoffState& aHandoffState)
+{
+  return new GenericFlingAnimation(aApzc,
+      aHandoffState.mChain,
+      aHandoffState.mIsHandoff,
+      aHandoffState.mScrolledApzc);
+}
+
 TimeStamp
 AsyncPanZoomController::GetFrameTime() const
 {
@@ -3011,11 +3019,7 @@ ParentLayerPoint AsyncPanZoomController::AttemptFling(const FlingHandoffState& a
   ScrollSnapToDestination();
   if (mState != SMOOTH_SCROLL) {
     SetState(FLING);
-    FlingAnimation *fling = new FlingAnimation(*this,
-        GetPlatformSpecificState(),
-        aHandoffState.mChain,
-        aHandoffState.mIsHandoff,
-        aHandoffState.mScrolledApzc);
+    AsyncPanZoomAnimation* fling = GetPlatformSpecificState()->CreateFlingAnimation(*this, aHandoffState);
     StartAnimation(fling);
   }
 

gfx/layers/apz/src/AsyncPanZoomController.h

@@ -69,6 +69,8 @@ class PlatformSpecificStateBase {
 public:
   virtual ~PlatformSpecificStateBase() = default;
   virtual AndroidSpecificState* AsAndroidSpecificState() { return nullptr; }
+  virtual AsyncPanZoomAnimation* CreateFlingAnimation(AsyncPanZoomController& aApzc,
+                                                      const FlingHandoffState& aHandoffState);
 };
 
 /*

gfx/layers/apz/src/GenericFlingAnimation.h

@@ -30,7 +30,6 @@ namespace layers {
 class GenericFlingAnimation: public AsyncPanZoomAnimation {
 public:
   GenericFlingAnimation(AsyncPanZoomController& aApzc,
-                        PlatformSpecificStateBase* aPlatformSpecificState,
                         const RefPtr<const OverscrollHandoffChain>& aOverscrollHandoffChain,
                         bool aFlingIsHandedOff,
                         const RefPtr<const AsyncPanZoomController>& aScrolledApzc)