Make ViewRoot the top of the ViewAndroid tree

content/browser/android/content_view_render_view.h

Index: content/browser/android/content_view_render_view.h
diff --git a/content/browser/android/content_view_render_view.h b/content/browser/android/content_view_render_view.h
index 0f4fd0771d5bab6f040dec2ee0f06312314408a1..640428f6f20c3ded9273a3781171677e969b9e1b 100644
--- a/content/browser/android/content_view_render_view.h
+++ b/content/browser/android/content_view_render_view.h
@@ -14,6 +14,10 @@
 #include "content/public/browser/android/compositor_client.h"
 #include "ui/gfx/native_widget_types.h"
 
+namespace ui {
+class ViewRoot;
+}
+
 namespace content {
 class Compositor;
 
@@ -22,9 +26,7 @@ class ContentViewRenderView : public CompositorClient {
   // Registers the JNI methods for ContentViewRender.
   static bool RegisterContentViewRenderView(JNIEnv* env);
 
-  ContentViewRenderView(JNIEnv* env,
-                        jobject obj,
-                        gfx::NativeWindow root_window);
+  ContentViewRenderView(JNIEnv* env, jobject obj, ui::ViewRoot* view_root);
 
   // Methods called from Java via JNI -----------------------------------------
   void Destroy(JNIEnv* env, const base::android::JavaParamRef<jobject>& obj);
@@ -59,7 +61,7 @@ class ContentViewRenderView : public CompositorClient {
 
   std::unique_ptr<content::Compositor> compositor_;
 
-  gfx::NativeWindow root_window_;
+  ui::ViewRoot* view_root_;
   int current_surface_format_;
 
   DISALLOW_COPY_AND_ASSIGN(ContentViewRenderView);