Introduce ViewRoot to forward input/view events to native

content/browser/web_contents/web_contents_view_android.cc

Index: content/browser/web_contents/web_contents_view_android.cc
diff --git a/content/browser/web_contents/web_contents_view_android.cc b/content/browser/web_contents/web_contents_view_android.cc
index 0dc8bf471cc26e6bdadcf88854b21981f2e4fa66..f63a72dbd223a6328bcfef444e07430421cbb9b7 100644
--- a/content/browser/web_contents/web_contents_view_android.cc
+++ b/content/browser/web_contents/web_contents_view_android.cc
@@ -83,8 +83,8 @@ WebContentsViewAndroid::WebContentsViewAndroid(
     : web_contents_(web_contents),
       content_view_core_(NULL),
       delegate_(delegate),
-      synchronous_compositor_client_(nullptr) {
-}
+      view_(this),
+      synchronous_compositor_client_(nullptr) {}
 
 WebContentsViewAndroid::~WebContentsViewAndroid() {
   if (view_.GetLayer())
@@ -237,6 +237,21 @@ void WebContentsViewAndroid::RenderViewSwappedIn(RenderViewHost* host) {
 void WebContentsViewAndroid::SetOverscrollControllerEnabled(bool enabled) {
 }
 
+void WebContentsViewAndroid::OnPhysicalBackingSizeChanged(int width,
+                                                          int height) {
+  // |SendScreenRects()| indirectly calls GetViewSize() that asks Java layer.
+  web_contents_->SendScreenRects();

[boliu, 2016/12/06 23:15:46]

so this code is duplicated from
ContentViewCoreImpl::SendScreenRectsAndResizeWidget, right?

I think the size change should not need to be forwarded to RWHVA from here.
Instead, RWHVA can be ViewClient as well, and listen to size updates.

[Jinsuk Kim, 2016/12/07 12:36:28]

Done.

+
+  RenderWidgetHostView* rwhv = !web_contents_->ShowingInterstitialPage() ?
+      web_contents_->GetRenderWidgetHostView() :
+      web_contents_->GetInterstitialPage()
+                    ->GetMainFrame()
+                    ->GetRenderViewHost()
+                    ->GetWidget()
+                    ->GetView();
+  (static_cast<RenderWidgetHostViewAndroid*>(rwhv))->WasResized();
+}
+
 void WebContentsViewAndroid::ShowContextMenu(
     RenderFrameHost* render_frame_host, const ContextMenuParams& params) {
   if (delegate_)