GN: Build rules and fixes for (almost) all mojo unittest targets

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',
@@ skipping 318 matching lines @@
         'application_manager/application_manager_export.h',
         'application_manager/background_shell_application_loader.cc',
         'application_manager/background_shell_application_loader.h',
       ],
       'export_dependent_settings': [
         '../base/third_party/dynamic_annotations/dynamic_annotations.gyp:dynamic_annotations',
         'mojo_base.gyp:mojo_application_bindings',
       ],
     },
     {
+      # GN version: //mojo/application_manager:unittests
       'target_name': 'mojo_application_manager_unittests',
       'type': 'executable',
       'dependencies': [
         '../base/base.gyp:base',
         '../testing/gtest.gyp:gtest',
         '../url/url.gyp:url_lib',
         'mojo_application_manager',
         'mojo_base.gyp:mojo_common_lib',
         'mojo_base.gyp:mojo_cpp_bindings',
         'mojo_base.gyp:mojo_environment_chromium',
@@ skipping 173 matching lines @@
             'views/views_init_internal.h',
           ],
           'defines': [
             'MOJO_VIEWS_IMPLEMENTATION',
           ],
         },
       ],
     }],
   ],
 }