Introduce ViewRoot to forward input/view events to native

ui/android/view_android.cc

Index: ui/android/view_android.cc
diff --git a/ui/android/view_android.cc b/ui/android/view_android.cc
index 664758cd5304088709f1cd99bdb655bae764aadf..0ab53036f2f8657783c7e05f476c4182717b8e4d 100644
--- a/ui/android/view_android.cc
+++ b/ui/android/view_android.cc
@@ -15,6 +15,7 @@
 
 namespace ui {
 
+using base::android::JavaParamRef;
 using base::android::JavaRef;
 using base::android::ScopedJavaLocalRef;
 
@@ -68,11 +69,6 @@ ViewAndroid::ScopedAnchorView::view() const {
   return view_.get(env);
 }
 
-ViewAndroid::ViewAndroid(const JavaRef<jobject>& delegate)
-    : parent_(nullptr)
-    , delegate_(base::android::AttachCurrentThread(),
-                delegate.obj()) {}
-
 ViewAndroid::ViewAndroid() : parent_(nullptr) {}
 
 ViewAndroid::~ViewAndroid() {
@@ -86,8 +82,13 @@ ViewAndroid::~ViewAndroid() {
 }
 
 void ViewAndroid::SetDelegate(const JavaRef<jobject>& delegate) {
+  // A ViewAndroid may have its own delegate or otherwise will
+  // use the next available parent's delegate.
   JNIEnv* env = base::android::AttachCurrentThread();
   delegate_ = JavaObjectWeakGlobalRef(env, delegate);
+  Java_ViewAndroidDelegate_setNativePointer(env,

[boliu, 2016/11/15 04:51:03]

delegate has a many-to-one relationship with view, right? don't think this will
work

[Jinsuk Kim, 2016/11/15 16:47:44]

My intention was to maintain only one handler per each api to keep one-to-one
mapping. 

+                                            delegate,
+                                            reinterpret_cast<jlong>(this));
 }
 
 void ViewAndroid::AddChild(ViewAndroid* child) {
@@ -179,4 +180,19 @@ bool ViewAndroid::StartDragAndDrop(const JavaRef<jstring>& jtext,
                                                    jimage);
 }
 
+void ViewAndroid::OnPhysicalBackingSizeChanged(
+    JNIEnv* env,
+    const JavaParamRef<jobject>& obj,
+    jint width, jint height) {
+  if (!physical_backing_size_changed_handler_.is_null()) {
+    physical_backing_size_changed_handler_.Run(width, height);
+    return;
+  }
+}
+
+// static
+bool ViewAndroid::RegisterViewAndroid(JNIEnv* env) {
+  return RegisterNativesImpl(env);
+}
+
 }  // namespace ui