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..2849109ead46b0eb33208a26a31dabdcd2373027 100644
--- a/ui/android/view_android.h
+++ b/ui/android/view_android.h
@@ -18,6 +18,7 @@ class Layer;
 
 namespace ui {
 
+class EventHandler;
 class WindowAndroid;
 
 // A simple container for a UI layer.
@@ -54,9 +55,14 @@ 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);
+  // Client interface used to forward events from Java to native views.
+  // Calls not handled by a client are dispatched to its children along
+  // the hierarchy of ViewAndroid. Overriden method should return true
+  // to indicate that the event was handled and stop the processing.
+  class ViewClient {

[boliu, 2016/12/02 23:53:22]

put this in a separate file, presumably this will grow a lot more in the future

[Jinsuk Kim, 2016/12/05 11:07:44]

Done.

+   public:
+    bool OnPhysicalBackingSizeChanged(int width, int height) { return false; }

[boliu, 2016/12/02 23:53:22]

virtual? also I think inlining virtual method is not allowed

[Jinsuk Kim, 2016/12/05 11:07:44]

Done.

+  };
 
   ViewAndroid();
   virtual ~ViewAndroid();
@@ -71,19 +77,28 @@ class UI_ANDROID_EXPORT ViewAndroid {
 
   void SetDelegate(const base::android::JavaRef<jobject>& delegate);
 
+  EventHandler* GetEventHandler();
+
   // Adds this view as a child of another view.
   void AddChild(ViewAndroid* child);
 
   // Detaches this view from its parent.
   void RemoveFromParent();
 
+  void SetViewClient(ViewClient* client) { client_ = client; }

[boliu, 2016/12/02 23:53:22]

can we pass this in on construction?

[Jinsuk Kim, 2016/12/05 11:07:44]

Done.

+
   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.
+  bool OnPhysicalBackingSizeChanged(int width, int height);
+
  protected:
   ViewAndroid* parent_;
 
@@ -99,6 +114,8 @@ class UI_ANDROID_EXPORT ViewAndroid {
   std::list<ViewAndroid*> children_;
   scoped_refptr<cc::Layer> layer_;
   JavaObjectWeakGlobalRef delegate_;
+  ViewClient* client_;
+  EventHandler* handler_;
 
   DISALLOW_COPY_AND_ASSIGN(ViewAndroid);
 };