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 461081dc723d4c338a3248725dc4a7e8e8bcdde1..631fe552a9ff05e1458c602fe8e32e265e235170 100644
--- a/content/browser/browser_plugin/browser_plugin_guest.cc
+++ b/content/browser/browser_plugin/browser_plugin_guest.cc
@@ -136,10 +136,19 @@ 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);
+  //
+  // TODO(ekaramad): We create the proxy for post messaging to the guest. The

[Charlie Reis, 2016/11/02 20:47:06]

nit: Say "to the guest below."  (I was having a hard time understanding how the
rest of this comment related to the code below, until I figured out that the
code below is creating the proxy that the embedder will use to talk to the
guest, rather than the "reverse" one the comment is describing.)

[EhsanK, 2016/11/08 23:10:16]

Sorry but I am a bit confused with the term "to the guest below" since |this| is
the guest as far as I understand.

I have reworded the comments; also changed the lines 129-133. Now in 129-135 we
explain the process of creating RFPH to post message to guest and how the
reverse one is created.

The TODO now only mentions that the reverse RFPH is not created when the
embedder is OOPIF.

+  // reverse route proxies are created when we first post message. However, if
+  // the guest is inisde an <iframe> (e.g., <embed>-ed PDF) then the reverse

[Charlie Reis, 2016/11/02 20:47:06]

nit: inside

[EhsanK, 2016/11/08 23:10:16]

Done.

+  // proxy is not created and the posted messages's source attribute is null.
+  // We should either create a RenderFrameProxyHost for the reverse path or
+  // implement MimeHandlerViewGuest's using OOPIF (https://crbug.com/659750).
+  SiteInstance* owner_site_instance = GetEmbedderFrame()->GetSiteInstance();
+  int proxy_routing_id = GetWebContents()
+                             ->GetFrameTree()
+                             ->root()
+                             ->render_manager()
+                             ->CreateRenderFrameProxy(owner_site_instance);
   guest_proxy_routing_id_ = RenderFrameProxyHost::FromID(
       owner_site_instance->GetProcess()->GetID(), proxy_routing_id)
           ->GetRenderViewHost()->GetRoutingID();
@@ -170,6 +179,10 @@ void BrowserPluginGuest::WillDestroy() {
   attached_ = false;
 }
 
+RenderFrameHostImpl* BrowserPluginGuest::GetEmbedderFrame() const {
+  return static_cast<RenderFrameHostImpl*>(delegate_->GetEmbedderFrame());
+}
+
 void BrowserPluginGuest::Init() {
   if (initialized_)
     return;
@@ -242,11 +255,10 @@ 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;

[Charlie Reis, 2016/11/02 20:47:06]

nit: Move these two lines above the "// Until" comment.

[EhsanK, 2016/11/08 23:10:16]

Done.

+  if (attached() && rwhv && rwhi &&
+      rwhv->OnMessageReceivedFromEmbedder(message, rwhi)) {
     return true;
   }
 
@@ -374,9 +386,10 @@ 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() {
@@ -448,8 +461,8 @@ void BrowserPluginGuest::ResendEventToEmbedder(
     return;
 
   DCHECK(browser_plugin_instance_id_);
-  RenderWidgetHostViewBase* view = static_cast<RenderWidgetHostViewBase*>(
-      embedder_web_contents()->GetMainFrame()->GetView());
+  RenderWidgetHostViewBase* view =
+      static_cast<RenderWidgetHostViewBase*>(GetOwnerRenderWidgetHostView());
 
   gfx::Vector2d offset_from_embedder = guest_window_rect_.OffsetFromOrigin();
   if (event.type == blink::WebInputEvent::GestureScrollUpdate) {
@@ -506,7 +519,8 @@ void BrowserPluginGuest::SendMessageToEmbedder(
     pending_messages_.push_back(std::move(msg));
     return;
   }
-  owner_web_contents_->Send(msg.release());
+
+  GetEmbedderFrame()->GetRenderWidgetHost()->Send(msg.release());

[Charlie Reis, 2016/11/02 20:47:06]

This change looks a little odd to me (sending via WebContents vs sending via
RenderWidgetHost), but I guess under the hood they're basically equivalent.  Ok.

[EhsanK, 2016/11/08 23:10:16]

To respect the exact implementation, we should send it to RenderWidgetHost
(since WebContents eventually does that under the hood).

However, we are handling these messages in BrowserPluginManager which is a
RenderThreadObserver. So, as I understand sending them to the embedder frame
directly also works. I wonder if we could alternatively send them to "any other"
IPC::Listener in the embedder process? (assuming that the browser side entity is
alive when RWH is).

 }
 
 void BrowserPluginGuest::DragSourceEndedAt(int client_x, int client_y,