Add a content API to create a message channel.

content/browser/android/content_view_core_impl.cc

Index: content/browser/android/content_view_core_impl.cc
diff --git a/content/browser/android/content_view_core_impl.cc b/content/browser/android/content_view_core_impl.cc
index 16e83d8a457ae3969bb8eed13a164c4879ec6290..62c4fed0611f792e137f470085958aff2b97cc79 100644
--- a/content/browser/android/content_view_core_impl.cc
+++ b/content/browser/android/content_view_core_impl.cc
@@ -26,6 +26,7 @@
 #include "content/browser/frame_host/navigation_entry_impl.h"
 #include "content/browser/geolocation/geolocation_dispatcher_host.h"
 #include "content/browser/media/media_web_contents_observer.h"
+#include "content/browser/message_port_service.h"
 #include "content/browser/renderer_host/compositor_impl_android.h"
 #include "content/browser/renderer_host/input/motion_event_android.h"
 #include "content/browser/renderer_host/input/web_input_event_builders_android.h"
@@ -158,6 +159,28 @@ float GetPrimaryDisplayDeviceScaleFactor() {
   return display.device_scale_factor();
 }
 
+void CreateMessageChannelOnIOThread(
+    MessagePortMessageFilter* filter,
+    int routing_id,
+    int* port1, int* port2) {
+
+  *port1 = 0;
+  *port2 = 0;
+  MessagePortService* msp = MessagePortService::GetInstance();
+  msp->Create(routing_id, filter, port1);
+  msp->Create(routing_id, filter, port2);
+  msp->QueueMessages(*port1);
+  msp->QueueMessages(*port2);
+}
+
+void OnMessageChannelCreated(
+    ScopedJavaGlobalRef<jobject>* callback,
+    int* port1, int* port2) {
+  JNIEnv* env = AttachCurrentThread();
+  Java_ContentViewCore_onMessageChannelCreated(env, *port1, *port2,
+      callback->obj());
+}
+
 }  // namespace
 
 // Enables a callback when the underlying WebContents is destroyed, to enable
@@ -1423,6 +1446,31 @@ void ContentViewCoreImpl::EvaluateJavaScript(JNIEnv* env,
       c_callback);
 }
 
+void ContentViewCoreImpl::CreateMessageChannel(JNIEnv* env, jobject obj,
+    jobject callback) {
+
+  ScopedJavaGlobalRef<jobject>* j_callback = new ScopedJavaGlobalRef<jobject>();
+  j_callback->Reset(env, callback);
+  RenderProcessHostImpl* rph =
+      static_cast<RenderProcessHostImpl*>(
+          web_contents_->GetRenderProcessHost());
+  MessagePortMessageFilter* mf = rph->message_port_message_filter();
+
+  int port1;

[Yaron, 2014/07/18 21:54:00]

These are stack allocated and are passing to another thread and back and the
callback will execute after this frame. I think instead you can new them and use
base::Owned on the reply to give the callback ownership.

[sgurun-gerrit only, 2014/10/28 00:41:10]

Done.

+  int port2;
+  // Create message channel on IO thread
+  BrowserThread::PostTaskAndReply(
+      BrowserThread::IO,
+      FROM_HERE,
+      base::Bind(&CreateMessageChannelOnIOThread,
+                 mf,
+                 GetWebContents()->GetRoutingID(),
+                 &port1, &port2),
+      base::Bind(&OnMessageChannelCreated,
+                 base::Owned(j_callback),
+                 &port1, &port2));
+}
+
 bool ContentViewCoreImpl::GetUseDesktopUserAgent(
     JNIEnv* env, jobject obj) {
   NavigationEntry* entry = web_contents_->GetController().GetVisibleEntry();