Android: Consolidate and simplify VSync logic

ui/base/android/window_android.h

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef UI_BASE_ANDROID_WINDOW_ANDROID_H_
 #define UI_BASE_ANDROID_WINDOW_ANDROID_H_
 
 #include <jni.h>
 #include <vector>
 #include "base/android/jni_helper.h"
 #include "base/android/scoped_java_ref.h"
 #include "base/observer_list.h"
+#include "base/time/time.h"
 #include "ui/base/ui_base_export.h"
 #include "ui/gfx/vector2d_f.h"
 
 namespace ui {
 
 class WindowAndroidCompositor;
 class WindowAndroidObserver;
 
 // Android implementation of the activity window.
 class UI_BASE_EXPORT WindowAndroid {
  public:
-  WindowAndroid(JNIEnv* env, jobject obj);
+  WindowAndroid(JNIEnv* env, jobject obj, jlong vsync_period);
 
   void Destroy(JNIEnv* env, jobject obj);
 
   base::android::ScopedJavaLocalRef<jobject> GetJavaObject();
 
   static bool RegisterWindowAndroid(JNIEnv* env);
 
   // The content offset is used to translate snapshots to the correct part of
   // the window.
   void set_content_offset(const gfx::Vector2dF& content_offset) {
     content_offset_ = content_offset;
   }
 
   bool GrabSnapshot(int content_x, int content_y, int width, int height,
                     std::vector<unsigned char>* png_representation);
 
   // Compositor callback relay.
   void OnCompositingDidCommit();
 
   void AttachCompositor(WindowAndroidCompositor* compositor);
   void DetachCompositor();
 
   void AddObserver(WindowAndroidObserver* observer);
   void RemoveObserver(WindowAndroidObserver* observer);
 
   WindowAndroidCompositor* GetCompositor() { return compositor_; }
 
+  void RequestVSyncUpdate();
+  void OnVSync(JNIEnv* env, jobject obj, jlong time_micros);
+
  private:
   ~WindowAndroid();
 
   JavaObjectWeakGlobalRef weak_java_window_;
   gfx::Vector2dF content_offset_;
   WindowAndroidCompositor* compositor_;
+  base::TimeDelta vsync_period_;
 
   ObserverList<WindowAndroidObserver> observer_list_;
 
   DISALLOW_COPY_AND_ASSIGN(WindowAndroid);
 };
 
 }  // namespace ui
 
 #endif  // UI_BASE_ANDROID_WINDOW_ANDROID_H_