Make ViewRoot the top of the ViewAndroid tree

ui/android/window_android.h

Index: ui/android/window_android.h
diff --git a/ui/android/window_android.h b/ui/android/window_android.h
index 7219c0ac73fa1c185f701323a07f79fd0115cce6..7a8b28cd3f9ba441216444ac5c0fa2519b39da8b 100644
--- a/ui/android/window_android.h
+++ b/ui/android/window_android.h
@@ -18,7 +18,6 @@
 #include "base/observer_list.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 cc {
@@ -35,8 +34,7 @@ class WindowAndroidCompositor;
 class WindowAndroidObserver;
 
 // Android implementation of the activity window.
-// WindowAndroid is also the root of a ViewAndroid tree.
-class UI_ANDROID_EXPORT WindowAndroid : public ViewAndroid {
+class UI_ANDROID_EXPORT WindowAndroid {
  public:
   WindowAndroid(JNIEnv* env, jobject obj, int display_id);
 
@@ -88,14 +86,11 @@ class UI_ANDROID_EXPORT WindowAndroid : public ViewAndroid {
   friend class DisplayAndroidManager;
   friend class WindowBeginFrameSource;
 
-  ~WindowAndroid() override;
+  ~WindowAndroid();
 
   void SetNeedsBeginFrames(bool needs_begin_frames);
   void RequestVSyncUpdate();
 
-  // ViewAndroid overrides.
-  WindowAndroid* GetWindowAndroid() const override;
-
   // The ID of the display that this window belongs to.
   int display_id() const { return display_id_; }