Make sure only platform app support <webview> tag

chrome/renderer/extensions/dispatcher.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 "chrome/renderer/extensions/dispatcher.h"
 
 #include "base/callback.h"
 #include "base/command_line.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/string_piece.h"
@@ skipping 963 matching lines @@
                                       context,
                                       v8_context);
       break;
     }
   }
 
   // Inject custom JS into the platform app context.
   if (IsWithinPlatformApp(frame))
     module_system->Require("platformApp");
 
-  if (context_type == Feature::BLESSED_EXTENSION_CONTEXT) {
+  // Only platform app need to support <webview> tag, "webView" and

[Charlie Reis, 2013/03/18 15:16:05]

Please fix typos:
Only platform apps support the <webview> tag, because the "webView" and

+  // "denyWebView" modules will effect the performace of the DOM modification

[Charlie Reis, 2013/03/18 15:16:05]

nit: will effect -> affect
nit: performance of DOM modifications

+  // (http://crbug.com/196453).
+  if (context_type == Feature::BLESSED_EXTENSION_CONTEXT &&
+       IsWithinPlatformApp(frame)) {

[PhistucK, 2013/03/18 17:50:41]

Just driving by -
Maybe cache the result of IsWithinPlatformApp(frame) in a variable and save a
microsecond? It is called a couple of lines prior to this line as well.

(I am not a C++ guy)

     // Note: setting up the WebView class here, not the chrome.webview API.
     // The API will be automatically set up when first used.
     if (extension->HasAPIPermission(APIPermission::kWebView)) {
       module_system->Require("webView");
       if (Feature::GetCurrentChannel() <= chrome::VersionInfo::CHANNEL_DEV)
         module_system->Require("webViewExperimental");
     } else {
       module_system->Require("denyWebView");
     }
   }
@@ skipping 326 matching lines @@
     std::string error_msg = base::StringPrintf(kMessage, function_name.c_str());
     v8::ThrowException(
         v8::Exception::Error(v8::String::New(error_msg.c_str())));
     return false;
   }
 
   return true;
 }
 
 }  // namespace extensions