Introduce ViewRoot to forward input/view events to native

content/browser/renderer_host/render_widget_host_view_android.cc

Index: content/browser/renderer_host/render_widget_host_view_android.cc
diff --git a/content/browser/renderer_host/render_widget_host_view_android.cc b/content/browser/renderer_host/render_widget_host_view_android.cc
index 08885281bf791989e0ea5321f566ba61adb0212a..a8f20b0ca3adfb75ad8cdd463d1a479a358f703d 100644
--- a/content/browser/renderer_host/render_widget_host_view_android.cc
+++ b/content/browser/renderer_host/render_widget_host_view_android.cc
@@ -440,6 +440,7 @@ RenderWidgetHostViewAndroid::RenderWidgetHostViewAndroid(
       content_view_core_(nullptr),
       ime_adapter_android_(this),
       cached_background_color_(SK_ColorWHITE),
+      view_(this),
       last_compositor_frame_sink_id_(kUndefinedCompositorFrameSinkId),
       gesture_provider_(ui::GetGestureProviderConfig(
                             ui::GestureProviderConfigType::CURRENT_PLATFORM),
@@ -718,7 +719,7 @@ gfx::Size RenderWidgetHostViewAndroid::GetPhysicalBackingSize() const {
         * ui::GetScaleFactorForNativeView(GetNativeView()));
   }
 
-  return content_view_core_->GetPhysicalBackingSize();
+  return view_.GetPhysicalBackingSize();
 }
 
 bool RenderWidgetHostViewAndroid::DoBrowserControlsShrinkBlinkSize() const {
@@ -803,6 +804,11 @@ void RenderWidgetHostViewAndroid::SetNeedsBeginFrames(bool needs_begin_frames) {
     outstanding_vsync_requests_ &= ~PERSISTENT_BEGIN_FRAME;
 }
 
+void RenderWidgetHostViewAndroid::OnPhysicalBackingSizeChanged(int width,
+                                                               int height) {
+  WasResized();
+}
+
 void RenderWidgetHostViewAndroid::OnStartContentIntent(
     const GURL& content_url, bool is_main_frame) {
   if (content_view_core_)