Don't show host permission warnings for platform apps.

chrome/browser/extensions/api/permissions/permissions_api.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/browser/extensions/api/permissions/permissions_api.h"
 
 #include "base/memory/scoped_ptr.h"
 #include "chrome/browser/extensions/api/permissions/permissions_api_helpers.h"
 #include "chrome/browser/extensions/extension_service.h"
 #include "chrome/browser/extensions/permissions_updater.h"
@@ skipping 183 matching lines @@
 
   // Filter out the granted permissions so we only prompt for new ones.
   requested_permissions_ = PermissionSet::CreateDifference(
       requested_permissions_.get(), granted.get());
 
   AddRef();  // Balanced in InstallUIProceed() / InstallUIAbort().
 
   // We don't need to show the prompt if there are no new warnings, or if
   // we're skipping the confirmation UI. All extension types but INTERNAL
   // are allowed to silently increase their permission level.
-  if (auto_confirm_for_tests == PROCEED ||
-      requested_permissions_->GetWarningMessages().size() == 0) {
+  bool has_no_warnings = requested_permissions_->GetWarningMessages(
+      GetExtension()->GetType()).size() == 0;
+  if (auto_confirm_for_tests == PROCEED || has_no_warnings) {
     InstallUIProceed();
   } else if (auto_confirm_for_tests == ABORT) {
     // Pretend the user clicked cancel.
     InstallUIAbort(true);
   } else {
     CHECK_EQ(DO_NOT_SKIP, auto_confirm_for_tests);
     install_ui_.reset(
         chrome::CreateExtensionInstallPromptWithBrowser(GetCurrentBrowser()));
     install_ui_->ConfirmPermissions(
         this, GetExtension(), requested_permissions_.get());
   }
 
   return true;
 }