s/\bArc\b/ARC/g for ARC related code.

chrome/browser/ui/ash/launcher/arc_app_shelf_id.h

 // Copyright 2016 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.
 
 #ifndef CHROME_BROWSER_UI_ASH_LAUNCHER_ARC_APP_SHELF_ID_H_
 #define CHROME_BROWSER_UI_ASH_LAUNCHER_ARC_APP_SHELF_ID_H_
 
 #include <string>
 
-// Represents Arc app shelf id that consists from app id and optional shelf
+// Represents ARC app shelf id that consists from app id and optional shelf
 // group id.
 namespace arc {
 
 class ArcAppShelfId {
  public:
   ArcAppShelfId(const std::string& shelf_group_id, const std::string& app_id);
   ArcAppShelfId(const ArcAppShelfId& other);
   ~ArcAppShelfId();
 
   // Returns id from string representation which has syntax
@@ skipping 18 matching lines @@
   const std::string& app_id() const { return app_id_; }
 
  private:
   const std::string shelf_group_id_;
   const std::string app_id_;
 };
 
 }  // namespace arc
 
 #endif  // CHROME_BROWSER_UI_ASH_LAUNCHER_ARC_APP_SHELF_ID_H_