Add simple mash context menu support.

chrome/browser/ui/BUILD.gn

 # 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.
 
 import("//build/config/crypto.gni")
 import("//build/config/features.gni")
 import("//build/config/ui.gni")
 import("//chrome/common/features.gni")
 
 gypi_values = exec_script("//build/gypi_to_gn.py",
@@ skipping 244 matching lines @@
       "//ui/base/ime",
     ]
   }
   if (use_cups) {
     configs += [ "//printing:cups" ]
   }
   if (use_ash) {
     sources +=
         rebase_path(gypi_values.chrome_browser_ui_ash_sources, ".", "//chrome")
     sources += [
+      "ash/context_menu.cc",
+      "ash/context_menu.h",
       "ash/keyboard_ui_service.cc",
       "ash/keyboard_ui_service.h",
     ]
     deps += [
       "//ash",
       "//ash:ash_with_content",
       "//ash/strings",
       "//components/user_manager",
+      "//mash/shelf/public/interfaces",
       "//ui/keyboard:mojom",
     ]
     if (!is_chromeos) {
       sources += rebase_path(gypi_values.chrome_browser_ui_ash_non_chromeos,
                              ".",
                              "//chrome")
     }
   } else {  # Not ash.
     sources += rebase_path(gypi_values.chrome_browser_ui_non_ash_sources,
                            ".",
@@ skipping 386 matching lines @@
     "//chrome/browser",
     "//content/public/browser",
     "//content/public/common",
     "//content/test:test_support",
     "//net:test_support",
     "//skia",
     "//testing/gtest",
     "//ui/base",
   ]
 }