Introduce ViewRoot forwarding input/view events to native

ui/android/view_android.h

Index: ui/android/view_android.h
diff --git a/ui/android/view_android.h b/ui/android/view_android.h
index d05520d514b7ee525f1b85ec78f8fb7ceb1cd04b..c024fee6862609425cdfd962513c167011e090d0 100644
--- a/ui/android/view_android.h
+++ b/ui/android/view_android.h
@@ -22,7 +22,7 @@ class ViewClient;
 class WindowAndroid;
 
 // A simple container for a UI layer.
-// At the root of the hierarchy is a WindowAndroid, when attached.
+// At the root of the hierarchy is a ViewRoot, a subclass of ViewAndroid.
 class UI_ANDROID_EXPORT ViewAndroid {
  public:
   // Stores an anchored view to delete itself at the end of its lifetime
@@ -64,9 +64,9 @@ class UI_ANDROID_EXPORT ViewAndroid {
   // if disconnected.
   virtual WindowAndroid* GetWindowAndroid() const;
 
-  // Returns |ViewRoot| associated with the current ViewAndroid.
-  // Create one if not present.
-  base::android::ScopedJavaLocalRef<jobject> GetViewRoot();
+  // Returns |ViewRoot| of this hierarchy. |null| if the hierarchy isn't
+  // attached to a |ViewRoot|.
+  virtual ViewAndroid* GetViewRoot();
 
   // Used to return and set the layer for this view. May be |null|.
   cc::Layer* GetLayer() const;
@@ -74,7 +74,7 @@ class UI_ANDROID_EXPORT ViewAndroid {
 
   void SetDelegate(const base::android::JavaRef<jobject>& delegate);
 
-  // Adds this view as a child of another view.
+  // Adds a child to this view.
   void AddChild(ViewAndroid* child);
 
   // Detaches this view from its parent.
@@ -90,21 +90,15 @@ class UI_ANDROID_EXPORT ViewAndroid {
   gfx::Size GetPhysicalBackingSize();
   void UpdateLayerBounds();
 
-  // Internal implementation of ViewClient forwarding calls to the interface.
-  void OnPhysicalBackingSizeChanged(int width, int height);
-
  protected:
-  ViewAndroid* parent_;
+  // Internal implementation of ViewClient forwarding calls to the interface.
+  void OnPhysicalBackingSizeChangedInternal(int width, int height);
 
  private:
-  void RemoveChild(ViewAndroid* child);
+  // Returns true only if this is of type |ViewRoot|.
+  bool IsViewRoot();
 
-  // Checks if any ViewAndroid instance in the tree hierarchy (including
-  // all the parents and the children) has |ViewRoot| already.
-  bool HasViewRootInTreeHierarchy();
-
-  // Checks if any children (plus this ViewAndroid itself) has |ViewRoot|.
-  bool HasViewRootInSubtree();
+  void RemoveChild(ViewAndroid* child);
 
   // Returns the Java delegate for this view. This is used to delegate work
   // up to the embedding view (or the embedder that can deal with the
@@ -116,12 +110,10 @@ class UI_ANDROID_EXPORT ViewAndroid {
   // should have |ViewRoot| for this ViewAndroid to have one.
   base::android::ScopedJavaLocalRef<jobject> CreateViewRoot();
 
-  bool HasViewRoot();
-
+  ViewAndroid* parent_;
   std::list<ViewAndroid*> children_;
   scoped_refptr<cc::Layer> layer_;
   JavaObjectWeakGlobalRef delegate_;
-  JavaObjectWeakGlobalRef view_root_;
   ViewClient* const client_;
 
   int physical_width_pix_;
@@ -130,8 +122,6 @@ class UI_ANDROID_EXPORT ViewAndroid {
   DISALLOW_COPY_AND_ASSIGN(ViewAndroid);
 };
 
-bool RegisterViewRoot(JNIEnv* env);
-
 }  // namespace ui
 
 #endif  // UI_ANDROID_VIEW_ANDROID_H_