Enable posting a message from JS to Android webview.

android_webview/browser/aw_browser_context.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 "android_webview/browser/aw_browser_context.h"
 
 #include "android_webview/browser/aw_form_database_service.h"
 #include "android_webview/browser/aw_pref_store.h"
 #include "android_webview/browser/aw_quota_manager_bridge.h"
 #include "android_webview/browser/aw_resource_context.h"
@@ skipping 219 matching lines @@
 
 data_reduction_proxy::DataReductionProxyConfigurator*
 AwBrowserContext::GetDataReductionProxyConfigurator() {
   return data_reduction_proxy_configurator_.get();
 }
 
 AwURLRequestContextGetter* AwBrowserContext::GetAwURLRequestContext() {
   return url_request_context_getter_.get();
 }
 
+AwMessagePortService* AwBrowserContext::GetMessagePortService() {
+  if (!message_port_service_.get()) {
+    message_port_service_.reset(
+        native_factory_->CreateAwMessagePortService());
+  }
+  return message_port_service_.get();
+}
+
 // Create user pref service for autofill functionality.
 void AwBrowserContext::CreateUserPrefServiceIfNecessary() {
   if (user_pref_service_)
     return;
 
   PrefRegistrySimple* pref_registry = new PrefRegistrySimple();
   // We only use the autocomplete feature of the Autofill, which is
   // controlled via the manager_delegate. We don't use the rest
   // of autofill, which is why it is hardcoded as disabled here.
   pref_registry->RegisterBooleanPref(
@@ skipping 117 matching lines @@
     data_reduction_proxy_statistics_ =
         scoped_ptr<data_reduction_proxy::DataReductionProxyStatisticsPrefs>(
             new data_reduction_proxy::DataReductionProxyStatisticsPrefs(
                 user_pref_service_.get(),
                 base::MessageLoopProxy::current(),
                 commit_delay));
   }
 }
 
 }  // namespace android_webview