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..93436c9bed28e47dc1c26b6fddd258282fd687f8 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 +237,22 @@ void WebContentsViewAndroid::RenderViewSwappedIn(RenderViewHost* host) {
 void WebContentsViewAndroid::SetOverscrollControllerEnabled(bool enabled) {
 }
 
+bool WebContentsViewAndroid::OnPhysicalBackingSizeChanged(int width,
+                                                          int height) {
+  // |SendScreenRects()| indirectly calls GetViewSize() that asks Java layer.
+  web_contents_->SendScreenRects();
+
+  RenderWidgetHostView* rwhv = !web_contents_->ShowingInterstitialPage() ?

[boliu, 2016/12/06 00:34:14]

it's not clear to me why WasResized should only called on the current RWHVA, but
not the "background" one, is there a precedence where the old code used to do
this?

eg is there code that updates the "background" RWHVA after the interstitial is
dismissed? WebContentsImpl::DidProceedOnInterstitial or DetachInterstitialPage
doesn't do this it seems


on the other hand, shouldn't each RWHVA get its own OnPhysicalBackingSizeChanged
implementation, and then can observe size updates?

[Jinsuk Kim, 2016/12/06 07:35:07]

I don't have good answers to your questions. You may be right in that each RWHVA
should get PBSC event but that's not what CVC was doing before this CL. It only
updates current RWHVA (either actual content or interstitial). 

[boliu, 2016/12/06 19:13:59]

afaict that's a bug in CVCImpl. Update both.

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

Done. I think the bug is addressed by letting each RWHVA observe physical
backing size update as in the updated patch.

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