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..c5df2973d3b198d40a1cf07a11a20b18d93bca8b 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.
@@ -54,11 +55,9 @@ 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();
 
   // Returns the window at the root of this hierarchy, or |null|
@@ -77,28 +76,59 @@ class UI_ANDROID_EXPORT ViewAndroid {
   // Detaches this view from its parent.
   void RemoveFromParent();
 
+  bool has_event_handler() { return has_event_handler_; }

[boliu, 2016/12/06 23:15:46]

private

[Jinsuk Kim, 2016/12/07 12:36:28]

Removed.

+
+  // Called when an |EventHandler| gets associated with the current ViewAndroid.
+  // The |EventHandler| must be unique in the tree to which this ViewAndroid

[boliu, 2016/12/06 23:15:46]

"unique in the tree" is not the phrase here, I don't have a good phrase either,
so just skip that part and describe what the condition actually is

[Jinsuk Kim, 2016/12/07 12:36:28]

Done.

+  // belongs - i.e. there must be no parent or child ViewAndroid instance that
+  // already has an |EventHandler|.
+  void OnSetEventHandler();
+
   bool StartDragAndDrop(const base::android::JavaRef<jstring>& jtext,
                         const base::android::JavaRef<jobject>& jimage);
 
+  gfx::Size GetPhysicalBackingSize();
+
   ScopedAnchorView AcquireAnchorView();
   void SetAnchorRect(const base::android::JavaRef<jobject>& anchor,
                      const gfx::RectF& bounds);
 
+  // Internal implementation of ViewClient forwarding calls to the interface.
+  void OnPhysicalBackingSizeChanged(int width, int height);
+
+  void UpdateLayerBounds();
+
  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 |EventHandler| already.
+  bool HasEventHandlerInTreeHierarchy();
+
+  // Checks if any children (plus this ViewAndroid itself) has |EventHandler|.
+  bool HasEventHandlerInSubtree();
+
   // 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;
 
+  int GetPhysicalBackingSizeWidthPix();

[boliu, 2016/12/06 23:15:46]

remove these two

[Jinsuk Kim, 2016/12/07 12:36:28]

Done.

+  int GetPhysicalBackingSizeHeightPix();
+  void SetPhysicalBackingSize(int width, int height);
+
   std::list<ViewAndroid*> children_;
   scoped_refptr<cc::Layer> layer_;
   JavaObjectWeakGlobalRef delegate_;
+  ViewClient* const client_;
+
+  int physical_width_pix_;
+  int physical_height_pix_;
+  bool has_event_handler_;
 
   DISALLOW_COPY_AND_ASSIGN(ViewAndroid);
 };