[cc] Remove BeginFrameAck from BFS::DidFinishFrame and update tests.

ui/android/window_android.cc

Index: ui/android/window_android.cc
diff --git a/ui/android/window_android.cc b/ui/android/window_android.cc
index 9f079b77c30024e59b9cfd00af14d1ab8e7dcdc8..388d4c6daad927a328350e5b0396f16394ca77d8 100644
--- a/ui/android/window_android.cc
+++ b/ui/android/window_android.cc
@@ -38,8 +38,7 @@ class WindowAndroid::WindowBeginFrameSource : public cc::BeginFrameSource {
   // cc::BeginFrameSource implementation.
   void AddObserver(cc::BeginFrameObserver* obs) override;
   void RemoveObserver(cc::BeginFrameObserver* obs) override;
-  void DidFinishFrame(cc::BeginFrameObserver* obs,
-                      const cc::BeginFrameAck& ack) override {}
+  void DidFinishFrame(cc::BeginFrameObserver* obs) override {}
   bool IsThrottled() const override { return true; }
 
   void OnVSync(base::TimeTicks frame_time, base::TimeDelta vsync_period);