Adds support for calling postMessage on a frame living in a different renderer.

content/browser/web_contents/web_contents_impl.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/browser/web_contents/web_contents_impl.h"
 
 #include <utility>
 
 #include "base/command_line.h"
 #include "base/metrics/histogram.h"
@@ skipping 2400 matching lines @@
 void WebContentsImpl::RouteCloseEvent(RenderViewHost* rvh) {
   // Tell the active RenderViewHost to run unload handlers and close, as long
   // as the request came from a RenderViewHost in the same BrowsingInstance.
   // In most cases, we receive this from a swapped out RenderViewHost.
   // It is possible to receive it from one that has just been swapped in,
   // in which case we might as well deliver the message anyway.
   if (rvh->GetSiteInstance()->IsRelatedSiteInstance(GetSiteInstance()))
     GetRenderViewHost()->ClosePage();
 }
 
+void WebContentsImpl::RouteMessageEvent(
+    RenderViewHost* rvh,
+    const ViewHostMsg_PostMessage_Params& params) {
+  // Deliver the message to the active RenderViewHost, as long as the request
+  // came from a RenderViewHost in the same BrowsingInstance.
+  if (rvh->GetSiteInstance()->IsRelatedSiteInstance(GetSiteInstance())) {
+    ViewHostMsg_PostMessage_Params new_params(params);
+
+    // If there is a source_routing_id, translate it to the routing ID for
+    // the equivalent swapped out RVH in the target process.  If we need
+    // to create a swapped out RVH for the source tab, we create its opener
+    // chain as well, since those will also be accessible to the target page.
+    if (new_params.source_routing_id != MSG_ROUTING_NONE) {
+      // Try to look up the WebContents for the source page.
+      WebContentsImpl* source_contents = NULL;
+      RenderViewHostImpl* source_rvh = RenderViewHostImpl::FromID(
+          rvh->GetProcess()->GetID(), params.source_routing_id);
+      RenderViewHostDelegate* source_delegate = source_rvh->GetDelegate();

[Matt Perry, 2012/05/11 21:59:34]

Is it possible for source_rvh to be NULL?

[Charlie Reis, 2012/05/11 22:36:02]

Good call.  Can't trust the renderer to pass a legit value.  Fixed.

+      if (source_delegate->GetRenderViewType() ==
+              content::VIEW_TYPE_WEB_CONTENTS) {
+        source_contents = static_cast<WebContentsImpl*>(source_delegate);
+      }
+
+      if (source_contents) {
+        new_params.source_routing_id =
+            source_contents->CreateOpenerRenderViews(GetSiteInstance());
+      } else {
+        // We couldn't find it, so don't pass a source frame.
+        new_params.source_routing_id = MSG_ROUTING_NONE;
+      }
+    }
+
+    // In most cases, we receive this from a swapped out RenderViewHost.
+    // It is possible to receive it from one that has just been swapped in,
+    // in which case we might as well deliver the message anyway.
+    GetRenderViewHost()->Send(new ViewMsg_PostMessageEvent(
+        GetRenderViewHost()->GetRoutingID(), new_params));
+  }
+}
+
 void WebContentsImpl::RunJavaScriptMessage(
     RenderViewHost* rvh,
     const string16& message,
     const string16& default_prompt,
     const GURL& frame_url,
     ui::JavascriptMessageType javascript_message_type,
     IPC::Message* reply_msg,
     bool* did_suppress_message) {
   // Suppress JavaScript dialogs when requested. Also suppress messages when
   // showing an interstitial as it's shown over the previous page and we don't
@@ skipping 298 matching lines @@
 void WebContentsImpl::CreateViewAndSetSizeForRVH(RenderViewHost* rvh) {
   RenderWidgetHostView* rwh_view = GetView()->CreateViewForWidget(rvh);
   // Can be NULL during tests.
   if (rwh_view)
     rwh_view->SetSize(GetView()->GetContainerSize());
 }
 
 RenderViewHostImpl* WebContentsImpl::GetRenderViewHostImpl() {
   return static_cast<RenderViewHostImpl*>(GetRenderViewHost());
 }