Add a basic postMessage test for <webview> in a new test suite.

chrome/browser/apps/guest_view/web_view_browsertest.cc

 // Copyright 2013 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 "base/path_service.h"
 #include "base/process/process.h"
 #include "base/strings/stringprintf.h"
 #include "base/strings/utf_string_conversions.h"
 #include "chrome/app/chrome_command_ids.h"
 #include "chrome/browser/apps/app_browsertest_util.h"
@@ skipping 826 matching lines @@
 
   scoped_ptr<content::FakeSpeechRecognitionManager>
       fake_speech_recognition_manager_;
 
   TestGuestViewManagerFactory factory_;
   // Note that these are only set if you launch app using LoadAppWithGuest().
   content::WebContents* guest_web_contents_;
   content::WebContents* embedder_web_contents_;
 };
 
+// Test suite that containts tests that are meant to run with and without
+// --site-per-process.
+class WebViewCommonTest : public extensions::PlatformAppBrowserTest {};
+
 class WebViewDPITest : public WebViewTest {
  protected:
   void SetUpCommandLine(base::CommandLine* command_line) override {
     WebViewTest::SetUpCommandLine(command_line);
     command_line->AppendSwitchASCII(switches::kForceDeviceScaleFactor,
                                     base::StringPrintf("%f", scale()));
   }
 
   static float scale() { return 2.0f; }
 };
@@ skipping 1847 matching lines @@
 // This test verifies that the allowtransparency attribute properly propagates
 IN_PROC_BROWSER_TEST_F(WebViewTest, AllowTransparencyAndAllowScalingPropagate) {
   LoadAppWithGuest("web_view/simple");
 
   ASSERT_TRUE(GetGuestWebContents());
   extensions::WebViewGuest* guest =
       extensions::WebViewGuest::FromWebContents(GetGuestWebContents());
   ASSERT_TRUE(guest->allow_transparency());
   ASSERT_TRUE(guest->allow_scaling());
 }
+
+IN_PROC_BROWSER_TEST_F(WebViewCommonTest, BasicPostMessage) {
+  ASSERT_TRUE(StartEmbeddedTestServer());  // For serving guest pages.
+  ASSERT_TRUE(RunPlatformAppTest("platform_apps/web_view/post_message/basic"))
+      << message_;
+}