[MD Feedback] Add placeholder feedback entry point.

chrome/browser/feedback/show_feedback_page.cc

 // Copyright 2014 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 <string>
 
 #include "build/build_config.h"
 #include "chrome/browser/browser_process.h"
 #include "chrome/browser/extensions/api/feedback_private/feedback_private_api.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/profiles/profile_manager.h"
 #include "chrome/browser/ui/ash/multi_user/multi_user_util.h"
 #include "chrome/browser/ui/ash/multi_user/multi_user_window_manager.h"
 #include "chrome/browser/ui/browser_finder.h"
 #include "chrome/browser/ui/browser_window.h"
 #include "chrome/browser/ui/tabs/tab_strip_model.h"
+#include "chrome/browser/ui/webui/md_feedback/md_feedback_dialog_controller.h"
+#include "chrome/common/chrome_switches.h"
 #include "components/signin/core/account_id/account_id.h"
 #include "content/public/browser/web_contents.h"
 #include "url/gurl.h"
 
 namespace {
 
 GURL GetTargetTabUrl(int session_id, int index) {
   Browser* browser = chrome::FindBrowserWithID(session_id);
   // Sanity checks.
   if (!browser || index >= browser->tab_strip_model()->count())
@@ skipping 44 matching lines @@
   const AccountId display_account_id =
       window_manager && browser
           ? window_manager->GetUserPresentingWindow(
                 browser->window()->GetNativeWindow())
           : EmptyAccountId();
   profile = display_account_id.is_valid()
                 ? multi_user_util::GetProfileFromAccountId(display_account_id)
                 : profile;
 #endif
 
+  if (::switches::MdFeedbackEnabled()) {
+    MdFeedbackDialogController* controller =
+        MdFeedbackDialogController::GetOrCreate();

[afakhry, 2016/08/02 22:15:56]

It's actually GetOrCreateAndGet() ;)
To be consistent with the rest of the code in the codebase, where Get() or
GetInstance() are far more common, you might want to call it just Get() and then
shorten your code like:

MdFeedbackDialogController::Get()->Show(profile);

[apacible, 2016/08/09 22:11:13]

Done.

+    controller->Show(profile);
+    return;
+  }
+
   extensions::FeedbackPrivateAPI* api =
       extensions::FeedbackPrivateAPI::GetFactoryInstance()->Get(profile);
 
   api->RequestFeedback(description_template,
                        category_tag,
                        page_url);
 }
 
 }  // namespace chrome