Add gclient hook to download prebuilt mojo_shell

mojo/mojo.gyp

 # Copyright 2013 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.
 
 {
   'target_defaults': {
     'conditions': [
       ['mojo_shell_debug_url != ""', {
         'defines': [
           'MOJO_SHELL_DEBUG=1',
           'MOJO_SHELL_DEBUG_URL="<(mojo_shell_debug_url)"',
          ],
       }],
     ],
   },
   'includes': [
     'mojo_apps.gypi',
     'mojo_converters.gypi',
     'mojo_services.gypi',
     'mojo_variables.gypi',
   ],
+  'variables': {
+    'use_prebuilt_mojo_shell%': 0,
+  },
   'targets': [
     {
       # GN version: //mojo
       'target_name': 'mojo',
       'type': 'none',
       'dependencies': [
         'edk/mojo_edk.gyp:mojo_edk',
         'mojo_application_manager',
         'mojo_application_manager_unittests',
         'mojo_apps_js_unittests',
@@ skipping 174 matching lines @@
       'dependencies': [
         'edk/mojo_edk.gyp:mojo_system_impl',
         'mojo_shell_lib',
       ],
       'sources': [
         'shell/shell_test_helper.cc',
         'shell/shell_test_helper.h',
       ],
     },
     {
-      # GN version: //mojo/shell
-      'target_name': 'mojo_shell',
-      'type': 'executable',
-      'dependencies': [
-        '../base/base.gyp:base',
-        'mojo_base.gyp:mojo_common_lib',
-        'mojo_base.gyp:mojo_environment_chromium',
-        'mojo_shell_lib',
-      ],
-      'sources': [
-        'shell/desktop/mojo_main.cc',
-      ],
-      'conditions': [
-        ['component=="shared_library"', {
-          'dependencies': [
-            '../ui/gfx/gfx.gyp:gfx',
-          ],
-        }],
-      ],
-    },
-    {
       # GN version: //mojo/shell:mojo_shell_tests
       'target_name': 'mojo_shell_tests',
       'type': '<(gtest_target_type)',
       'dependencies': [
         '../base/base.gyp:base',
         '../base/base.gyp:base_i18n',
         '../base/base.gyp:test_support_base',
         '../testing/gtest.gyp:gtest',
         '../net/net.gyp:net_test_support',
         '../url/url.gyp:url_lib',
@@ skipping 164 matching lines @@
         'public/mojo_public.gyp:mojo_environment_standalone',
         'public/mojo_public.gyp:mojo_public_test_interfaces',
         'public/mojo_public.gyp:mojo_utility',
       ],
       'sources': [
         'bindings/js/tests/run_js_tests.cc',
       ],
     },
   ],
   'conditions': [
+    ['<(use_prebuilt_mojo_shell)==1', {
+      'targets': [
+        {
+          # GN version: //mojo/public/tools:mojo_shell
+          'target_name': 'mojo_shell',
+          'type': 'none',
+          'copies': [{
+            'destination': '<(PRODUCT_DIR)',
+            'files': [
+              'public/tools/prebuilt/mojo_shell',
+            ],
+          }],
+        },
+      ]
+    }, {  # use_prebuilt_mojo_shell != 1
+      'targets': [
+        {
+          # GN version: //mojo/shell
+          'target_name': 'mojo_shell',
+          'type': 'executable',
+          'dependencies': [
+            '../base/base.gyp:base',
+            'mojo_base.gyp:mojo_common_lib',
+            'mojo_base.gyp:mojo_environment_chromium',
+            'mojo_shell_lib',
+          ],
+          'sources': [
+            'shell/desktop/mojo_main.cc',
+          ],
+          'conditions': [
+            ['component=="shared_library"', {
+              'dependencies': [
+                '../ui/gfx/gfx.gyp:gfx',
+              ],
+            }],
+          ],
+        },
+      ],
+    }],
     ['OS=="android"', {
       'targets': [
         {
           'target_name': 'mojo_native_viewport_java',
           'type': 'none',
           'dependencies': [
             '../base/base.gyp:base_java',
           ],
           'variables': {
             'java_in_dir': '<(DEPTH)/mojo/services/native_viewport/android',
@@ skipping 295 matching lines @@
             '../build/isolate.gypi',
           ],
           'sources': [
             'mojo_js_unittests.isolate',
           ],
         },
       ],
     }],
   ],
 }