[DRAFT] Add new default stylesheet for platform apps.

chrome/browser/renderer_host/chrome_render_view_host_observer.cc

Index: chrome/browser/renderer_host/chrome_render_view_host_observer.cc
diff --git a/chrome/browser/renderer_host/chrome_render_view_host_observer.cc b/chrome/browser/renderer_host/chrome_render_view_host_observer.cc
index 586ecdab8e907750bb0fc7323156cd2355f8b47c..a9ac0e5c980c8c5c8a30436cebeec945639b9caf 100644
--- a/chrome/browser/renderer_host/chrome_render_view_host_observer.cc
+++ b/chrome/browser/renderer_host/chrome_render_view_host_observer.cc
@@ -12,6 +12,7 @@
 #include "chrome/common/chrome_notification_types.h"
 #include "chrome/common/chrome_switches.h"
 #include "chrome/common/extensions/extension_messages.h"
+#include "chrome/common/extensions/platform_app_messages.h"
 #include "chrome/common/render_messages.h"
 #include "chrome/common/url_constants.h"
 #include "content/browser/browsing_instance.h"
@@ -107,6 +108,9 @@ void ChromeRenderViewHostObserver::InitRenderViewForExtensions() {
     profile_->GetExtensionService()->SetInstalledAppForRenderer(
         process->id(), extension);
   }
+  if (extension->is_platform_app()) {
+    Send(new PlatformAppMsg_IsPlatformApp());
+  }
 
   // Some extensions use chrome:// URLs.
   Extension::Type type = extension->GetType();