Introduce ViewRoot to forward input/view events to native

ui/android/event_handler.cc

+// Copyright (c) 2016 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.
+
+#include "ui/android/event_handler.h"
+
+#include "jni/EventHandler_jni.h"
+#include "ui/android/view_android.h"
+
+namespace ui {
+
+EventHandler::EventHandler(ui::ViewAndroid* view) : view_(view) { }
+
+void EventHandler::OnPhysicalBackingSizeChanged(JNIEnv* env,
+    const base::android::JavaParamRef<jobject>& obj,
+    int width,
+    int height) {
+  if (physical_width_pix_ == width && physical_height_pix_ == height)
+    return;
+  physical_width_pix_ = width;
+  physical_height_pix_ = height;
+
+  view_->OnPhysicalBackingSizeChanged(width, height);
+}
+
+int EventHandler::GetPhysicalBackingSizeWidthPix() {
+  return physical_width_pix_;
+}
+
+int EventHandler::GetPhysicalBackingSizeHeightPix() {
+  return physical_height_pix_;
+}
+
+bool RegisterEventHandler(JNIEnv* env) {
+  return RegisterNativesImpl(env);
+}
+
+}  // namespace content