Introduce ViewRoot to forward input/view events to native

ui/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_ANDROID_WINDOW_ANDROID_H_
 #define UI_ANDROID_WINDOW_ANDROID_H_
 
 #include <jni.h>
 #include <string>
 #include <vector>
@@ skipping 56 matching lines @@
                const base::android::JavaParamRef<jobject>& obj,
                jlong time_micros,
                jlong period_micros);
   void OnVisibilityChanged(JNIEnv* env,
                            const base::android::JavaParamRef<jobject>& obj,
                            bool visible);
   void OnActivityStopped(JNIEnv* env,
                          const base::android::JavaParamRef<jobject>& obj);
   void OnActivityStarted(JNIEnv* env,
                          const base::android::JavaParamRef<jobject>& obj);
+  base::android::ScopedJavaLocalRef<jobject> GetEventHandler(JNIEnv* env,
+      const base::android::JavaParamRef<jobject>& obj);
 
   // Return whether the specified Android permission is granted.
   bool HasPermission(const std::string& permission);
   // Return whether the specified Android permission can be requested by Chrome.
   bool CanRequestPermission(const std::string& permission);
 
   static WindowAndroid* CreateForTesting();
   void DestroyForTesting();
 
  private:
   friend class DisplayAndroidManager;
 
   ~WindowAndroid() override;
 
   // ViewAndroid overrides.
+  using ViewAndroid::GetEventHandler;
   WindowAndroid* GetWindowAndroid() const override;
 
   // The ID of the display that this window belongs to.
   int display_id() const { return display_id_; }
 
   base::android::ScopedJavaGlobalRef<jobject> java_window_;
   const int display_id_;
   gfx::Vector2dF content_offset_;
   WindowAndroidCompositor* compositor_;
 
   base::ObserverList<WindowAndroidObserver> observer_list_;
 
   DISALLOW_COPY_AND_ASSIGN(WindowAndroid);
 };
 
 }  // namespace ui
 
 #endif  // UI_ANDROID_WINDOW_ANDROID_H_