Introduce ViewRoot to forward 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 607a1acc72ae4dad10cfc8216cd5d76831b33c6f..d05520d514b7ee525f1b85ec78f8fb7ceb1cd04b 100644
--- a/ui/android/view_android.h
+++ b/ui/android/view_android.h
@@ -18,6 +18,7 @@ class Layer;
 
 namespace ui {
 
+class ViewClient;
 class WindowAndroid;
 
 // A simple container for a UI layer.
@@ -54,9 +55,7 @@ class UI_ANDROID_EXPORT ViewAndroid {
     // Default copy/assign disabled by move constructor.
   };
 
-  // A ViewAndroid may have its own delegate or otherwise will
-  // use the next available parent's delegate.
-  ViewAndroid(const base::android::JavaRef<jobject>& delegate);
+  explicit ViewAndroid(ViewClient* client);
 
   ViewAndroid();
   virtual ~ViewAndroid();
@@ -65,6 +64,10 @@ 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();
+
   // Used to return and set the layer for this view. May be |null|.
   cc::Layer* GetLayer() const;
   void SetLayer(scoped_refptr<cc::Layer> layer);
@@ -84,25 +87,51 @@ class UI_ANDROID_EXPORT ViewAndroid {
   void SetAnchorRect(const base::android::JavaRef<jobject>& anchor,
                      const gfx::RectF& bounds);
 
+  gfx::Size GetPhysicalBackingSize();
+  void UpdateLayerBounds();
+
+  // Internal implementation of ViewClient forwarding calls to the interface.
+  void OnPhysicalBackingSizeChanged(int width, int height);
+
  protected:
   ViewAndroid* parent_;
 
  private:
   void RemoveChild(ViewAndroid* child);
 
+  // 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();
+
   // 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
   // implementation details).
   const base::android::ScopedJavaLocalRef<jobject>
       GetViewAndroidDelegate() const;
 
+  // Creates a new |ViewRoot| for this ViewAndroid. No parent or child
+  // should have |ViewRoot| for this ViewAndroid to have one.
+  base::android::ScopedJavaLocalRef<jobject> CreateViewRoot();
+
+  bool HasViewRoot();
+
   std::list<ViewAndroid*> children_;
   scoped_refptr<cc::Layer> layer_;
   JavaObjectWeakGlobalRef delegate_;
+  JavaObjectWeakGlobalRef view_root_;
+  ViewClient* const client_;
+
+  int physical_width_pix_;
+  int physical_height_pix_;
 
   DISALLOW_COPY_AND_ASSIGN(ViewAndroid);
 };
 
+bool RegisterViewRoot(JNIEnv* env);
+
 }  // namespace ui
 
 #endif  // UI_ANDROID_VIEW_ANDROID_H_