Allow MimeHandlerViewGuest be embedded inside OOPIFs

content/browser/browser_plugin/browser_plugin_guest.cc

Index: content/browser/browser_plugin/browser_plugin_guest.cc
diff --git a/content/browser/browser_plugin/browser_plugin_guest.cc b/content/browser/browser_plugin/browser_plugin_guest.cc
index bcb8464383290287d0f6998aa759a6589b3020f2..5f9c8a43288d3b2b65973c838bb437cb83e05008 100644
--- a/content/browser/browser_plugin/browser_plugin_guest.cc
+++ b/content/browser/browser_plugin/browser_plugin_guest.cc
@@ -135,10 +135,13 @@ int BrowserPluginGuest::GetGuestProxyRoutingID() {
   // owners in different processes. We probably need to clear the
   // |guest_proxy_routing_id_| and perform any necessary cleanup on Detach
   // to enable this.
-  SiteInstance* owner_site_instance = owner_web_contents_->GetSiteInstance();
-  int proxy_routing_id =
-      GetWebContents()->GetFrameTree()->root()->render_manager()->
-          CreateRenderFrameProxy(owner_site_instance);
+  SiteInstance* owner_site_instance =
+      GetEmbedderFrame()->render_view_host()->GetSiteInstance();

[lfg, 2016/10/20 22:50:49]

GetEmbedderFrame()->GetSiteInstance().

[EhsanK, 2016/10/25 19:30:50]

Acknowledged.

+  int proxy_routing_id = GetWebContents()
+                             ->GetFrameTree()
+                             ->root()

[lfg, 2016/10/20 22:50:49]

I think the proxy has to be created in the embedder's FrameTreeNode.

[EhsanK, 2016/10/25 19:30:50]

I think the way it is and was defined is to setup the proxy inside the embedder
for the incoming post messages to guest. Then with the first message, we
initialize the proxy for the |message.source|. For that, I guess this part is
correct.

There were a couple of other places where I had to send the IPCs to the right
renderer to make sure MimeHandlerViewContainer is initialized properly. With
those changes in this patch, post message is half-working, i.e., we can post
message to the <embed>-ed PDF (e.g., sending a message {type: selectAll} will
select all text in PDF or we can send the print command). 

But unfortunately, we create the proxy for return trip of the message only in
the WebContents root node:
https://cs.chromium.org/chromium/src/content/browser/web_contents/web_content...

And we actually cannot create in a child node due to this CHECK:
https://cs.chromium.org/chromium/src/content/browser/frame_host/render_frame_...

Because we do not add the RFPH to the (right?) node, the source proxy is null
here:
https://cs.chromium.org/chromium/src/content/browser/frame_host/render_frame_...
And therefore, there is no |message.source|. There is some discussion in the bug
listed in the comment for the last link (https//crbug.com/485520).

I will add nasko@ to this CL for reviews and feedback on whether or not we would
like to have the post message supported in this CL.

[lfg, 2016/10/27 15:53:23]

Right, we should then add a TODO, and probably shouldn't be creating the proxy
in this case.

+                             ->render_manager()
+                             ->CreateRenderFrameProxy(owner_site_instance);
   guest_proxy_routing_id_ = RenderFrameProxyHost::FromID(
       owner_site_instance->GetProcess()->GetID(), proxy_routing_id)
           ->GetRenderViewHost()->GetRoutingID();
@@ -169,6 +172,10 @@ void BrowserPluginGuest::WillDestroy() {
   attached_ = false;
 }
 
+RenderFrameHostImpl* BrowserPluginGuest::GetEmbedderFrame() const {
+  return static_cast<RenderFrameHostImpl*>(delegate_->GetEmbedderFrame());
+}
+
 void BrowserPluginGuest::Init() {
   if (initialized_)
     return;
@@ -241,11 +248,11 @@ bool BrowserPluginGuest::OnMessageReceivedFromEmbedder(
   RenderWidgetHostViewGuest* rwhv = static_cast<RenderWidgetHostViewGuest*>(
       web_contents()->GetRenderWidgetHostView());
   // Until the guest is attached, it should not be handling input events.
-  if (attached() && rwhv &&
-      rwhv->OnMessageReceivedFromEmbedder(
-          message,
-          RenderWidgetHostImpl::From(
-              embedder_web_contents()->GetRenderViewHost()->GetWidget()))) {
+  RenderFrameHostImpl* rfhi = GetEmbedderFrame();
+  RenderWidgetHostImpl* rwhi = rfhi ? rfhi->GetRenderWidgetHost() : nullptr;
+  if (attached() && rwhv && rwhi &&
+      rwhv->OnMessageReceivedFromEmbedder(message,
+                                          RenderWidgetHostImpl::From(rwhi))) {

[lfg, 2016/10/20 22:50:49]

From is unnecessary.

[EhsanK, 2016/10/25 19:30:50]

Done.

     return true;
   }
 
@@ -373,9 +380,10 @@ bool BrowserPluginGuest::IsGuest(RenderViewHostImpl* render_view_host) {
 }
 
 RenderWidgetHostView* BrowserPluginGuest::GetOwnerRenderWidgetHostView() {
-  if (!owner_web_contents_)
-    return nullptr;
-  return owner_web_contents_->GetRenderWidgetHostView();
+  if (GetEmbedderFrame())
+    return GetEmbedderFrame()->GetView();
+
+  return nullptr;
 }
 
 void BrowserPluginGuest::UpdateVisibility() {
@@ -447,8 +455,8 @@ void BrowserPluginGuest::ResendEventToEmbedder(
     return;
 
   DCHECK(browser_plugin_instance_id_);
-  RenderWidgetHostViewBase* view = static_cast<RenderWidgetHostViewBase*>(
-      embedder_web_contents()->GetMainFrame()->GetView());
+  RenderWidgetHostViewBase* view =
+      static_cast<RenderWidgetHostViewBase*>(GetEmbedderFrame()->GetView());

[lfg, 2016/10/20 22:50:49]

GetOwnerRenderWidgetHostView().

[EhsanK, 2016/10/25 19:30:50]

Acknowledged.

 
   gfx::Vector2d offset_from_embedder = guest_window_rect_.OffsetFromOrigin();
   if (event.type == blink::WebInputEvent::GestureScrollUpdate) {
@@ -504,7 +512,8 @@ void BrowserPluginGuest::SendMessageToEmbedder(IPC::Message* msg) {
     pending_messages_.push_back(linked_ptr<IPC::Message>(msg));
     return;
   }
-  owner_web_contents_->Send(msg);
+
+  GetEmbedderFrame()->GetRenderWidgetHost()->Send(msg);
 }
 
 void BrowserPluginGuest::DragSourceEndedAt(int client_x, int client_y,