Enable posting a message from JS to Android webview.

content/browser/message_port_provider.cc

 // Copyright 2014 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/public/browser/message_port_provider.h"
 
 #include "base/basictypes.h"
 #include "content/browser/browser_thread_impl.h"
 #include "content/browser/message_port_message_filter.h"
 #include "content/browser/message_port_service.h"
 #include "content/browser/renderer_host/render_process_host_impl.h"
 #include "content/browser/renderer_host/render_view_host_impl.h"
 #include "content/browser/web_contents/web_contents_impl.h"
 #include "content/common/view_messages.h"
+#include "content/public/browser/message_port_delegate.h"
 
 namespace content {
 
+namespace {
+
+void PostMessageOnIOThread(MessagePortMessageFilter* filter,

[mnaganov (inactive), 2015/01/13 10:37:51]

Perhaps, you can now make this function a public method of
MessagePortMessageFilter itself?

[sgurun-gerrit only, 2015/01/14 23:53:13]

Let's leave it to later in case there is a demand, since it is pretty simple to
do. Or let me know if you feel strongly and I will do it.

[mnaganov (inactive), 2015/01/15 09:49:33]

Oh, again -- I was wrongly supposing that MessagePortMessageFilter is entirely
yours, but now I see that it is actually a generic class used by all postMessage
implementations, in that case modifying it just for this case doesn't really
make sense. Sorry!

+                           int routing_id,
+                           ViewMsg_PostMessage_Params* params) {
+  if (!params->message_port_ids.empty()) {
+    filter->UpdateMessagePortsWithNewRoutes(params->message_port_ids,
+                                            &params->new_routing_ids);
+  }
+  filter->Send(new ViewMsg_PostMessageEvent(routing_id, *params));
+}
+
+}  // namespace
+
+// static
 void MessagePortProvider::PostMessageToFrame(
     WebContents* web_contents,
     const base::string16& source_origin,
     const base::string16& target_origin,
     const base::string16& data,
     const std::vector<int>& ports) {
-  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
+  DCHECK_CURRENTLY_ON(BrowserThread::UI);
 
-  RenderViewHost* rvh = web_contents->GetRenderViewHost();
-  if (!rvh)
-    return;
+  ViewMsg_PostMessage_Params* params = new ViewMsg_PostMessage_Params();
+  params->is_data_raw_string = true;
+  params->data = data;
+  // Blink requires a source frame to transfer ports. This is why a
+  // source routing id is set here. See WebDOMMessageEvent::initMessageEvent()
+  params->source_routing_id = web_contents->GetRoutingID();
+  params->source_origin = source_origin;
+  params->target_origin = target_origin;
+  params->message_port_ids = ports;
 
-  ViewMsg_PostMessage_Params params;
-  params.is_data_raw_string = true;
-  params.data = data;
-  params.source_routing_id = web_contents->GetRoutingID();
-  params.source_origin = source_origin;
-  params.target_origin = target_origin;
   RenderProcessHostImpl* rph =
-      static_cast<RenderProcessHostImpl*>(
-          web_contents->GetRenderProcessHost());
+      static_cast<RenderProcessHostImpl*>(web_contents->GetRenderProcessHost());
   MessagePortMessageFilter* mf = rph->message_port_message_filter();
-
-  if (!ports.empty()) {
-    params.message_port_ids = ports;
-    mf->UpdateMessagePortsWithNewRoutes(params.message_port_ids,
-                                        &params.new_routing_ids);
-  }
-  rvh->Send(new ViewMsg_PostMessageEvent(
-                web_contents->GetRenderViewHost()->GetRoutingID(),
-                params));
+  BrowserThread::PostTask(
+      BrowserThread::IO,
+      FROM_HERE,
+      base::Bind(&PostMessageOnIOThread,
+                 make_scoped_refptr(mf),
+                 web_contents->GetRoutingID(),
+                 base::Owned(params)));
 }
 
-void MessagePortProvider::CreateMessageChannel(WebContents* web_contents,
+// static
+void MessagePortProvider::CreateMessageChannel(MessagePortDelegate* delegate,
                                                int* port1,
                                                int* port2) {
-  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
-
+  DCHECK_CURRENTLY_ON(BrowserThread::IO);
   *port1 = 0;
   *port2 = 0;
-
-  RenderProcessHostImpl* rph =
-      static_cast<RenderProcessHostImpl*>(
-          web_contents->GetRenderProcessHost());
-  MessagePortMessageFilter* mf = rph->message_port_message_filter();
   MessagePortService* msp = MessagePortService::GetInstance();
-  msp->Create(mf->GetNextRoutingID(), mf, port1);
-  msp->Create(mf->GetNextRoutingID(), mf, port2);
+  msp->Create(MSG_ROUTING_NONE, delegate, port1);
+  msp->Create(MSG_ROUTING_NONE, delegate, port2);
+  // Update the routing number of the message ports to be equal to the message
+  // port numbers.
+  msp->UpdateMessagePort(*port1, delegate, *port1);
+  msp->UpdateMessagePort(*port2, delegate, *port2);
   msp->Entangle(*port1, *port2);
   msp->Entangle(*port2, *port1);
 }
 
+// static
+void MessagePortProvider::OnMessagePortDelegateClosing(
+    MessagePortDelegate* delegate) {
+  MessagePortService::GetInstance()->OnMessagePortDelegateClosing(delegate);
+}
+
 } // namespace content