Introduce ViewRoot forwarding input/view events to native

ui/android/view_root.h

+// Copyright 2017 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_VIEW_ROOT_H_
+#define UI_ANDROID_VIEW_ROOT_H_
+
+#include <jni.h>
+#include <string>
+#include <vector>
+
+#include "base/android/jni_weak_ref.h"
+#include "base/android/scoped_java_ref.h"
+#include "base/macros.h"
+#include "base/time/time.h"
+#include "ui/android/ui_android_export.h"
+#include "ui/android/view_android.h"
+#include "ui/gfx/geometry/vector2d_f.h"
+
+namespace ui {
+
+// ViewRoot is the root of a ViewAndroid tree.
+class UI_ANDROID_EXPORT ViewRoot : public ViewAndroid {
+ public:
+  explicit ViewRoot(jlong window_android_ptr);
+
+  void Destroy(JNIEnv* env,
+               const base::android::JavaParamRef<jobject>& obj);
+
+  // ViewAndroid overrides.
+  WindowAndroid* GetWindowAndroid() const override;
+  ViewAndroid* GetViewRoot() override;
+
+  void OnPhysicalBackingSizeChanged(
+      JNIEnv* env,
+      const base::android::JavaParamRef<jobject>& jobj,
+      int width,
+      int height);
+
+ private:
+  WindowAndroid* window_;
+
+  DISALLOW_COPY_AND_ASSIGN(ViewRoot);
+};
+
+bool RegisterViewRoot(JNIEnv* env);
+
+}  // namespace ui
+
+#endif  // UI_ANDROID_VIEW_ROOT_H_