Introduce ViewRoot to forward input/view events to native

ui/android/window_android.cc

Index: ui/android/window_android.cc
diff --git a/ui/android/window_android.cc b/ui/android/window_android.cc
index cff32ba6f571def1c787cd219296027d86f1cbc8..a22d7af1a3bf90f5d1234fd3a121fde2cda38285 100644
--- a/ui/android/window_android.cc
+++ b/ui/android/window_android.cc
@@ -55,6 +55,13 @@ void WindowAndroid::DestroyForTesting() {
   delete this;
 }
 
+ScopedJavaLocalRef<jobject>
+WindowAndroid::CreateEventHandler(ViewAndroid* native_view) {
+  JNIEnv* env = base::android::AttachCurrentThread();
+  return Java_WindowAndroid_createEventHandler(env, GetJavaObject(),
+      reinterpret_cast<intptr_t>(native_view));
+}
+
 void WindowAndroid::OnCompositingDidCommit() {
   for (WindowAndroidObserver& observer : observer_list_)
     observer.OnCompositingDidCommit();
@@ -132,6 +139,12 @@ void WindowAndroid::OnActivityStarted(JNIEnv* env,
     observer.OnActivityStarted();
 }
 
+ScopedJavaLocalRef<jobject> WindowAndroid::GetEventHandler(
+    JNIEnv* env,
+    const base::android::JavaParamRef<jobject>& obj) {
+  return GetEventHandler();
+}
+
 bool WindowAndroid::HasPermission(const std::string& permission) {
   JNIEnv* env = AttachCurrentThread();
   return Java_WindowAndroid_hasPermission(