Only build various flash/pnacl/ppapi code when they are enabled.

chrome/chrome_common.gypi

 # Copyright (c) 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.
 
 {
   'variables': {
     # File lists shared with GN build.
     'chrome_common_sources': [
       '../apps/app_shim/app_shim_launch.h',
       '../apps/app_shim/app_shim_messages.h',
@@ skipping 131 matching lines @@
       'common/media/webrtc_logging_message_data.cc',
       'common/media/webrtc_logging_message_data.h',
       'common/media_galleries/metadata_types.h',
       'common/multi_process_lock.h',
       'common/multi_process_lock_linux.cc',
       'common/multi_process_lock_mac.cc',
       'common/multi_process_lock_win.cc',
       'common/omnibox_focus_state.h',
       'common/partial_circular_buffer.cc',
       'common/partial_circular_buffer.h',
-      'common/pepper_flash.cc',
-      'common/pepper_flash.h',
-      'common/pepper_permission_util.cc',
-      'common/pepper_permission_util.h',
       'common/pref_names_util.cc',
       'common/pref_names_util.h',
       'common/prerender_types.h',
       'common/print_messages.cc',
       'common/print_messages.h',
       'common/profiling.cc',
       'common/profiling.h',
       'common/ref_counted_util.h',
       'common/render_messages.cc',
       'common/render_messages.h',
@@ skipping 202 matching lines @@
             '<(DEPTH)/chrome/common/extensions/api/api.gyp:chrome_api',
             '<(DEPTH)/components/components.gyp:autofill_core_common',
             '<(DEPTH)/components/components.gyp:autofill_content_common',
             '<(DEPTH)/components/components.gyp:password_manager_core_common',
             '<(DEPTH)/components/components.gyp:signin_core_common',
             '<(DEPTH)/components/components.gyp:translate_content_common',
             '<(DEPTH)/components/components.gyp:visitedlink_common',
             '<(DEPTH)/extensions/common/api/api.gyp:extensions_api',
             '<(DEPTH)/extensions/extensions.gyp:extensions_common',
             '<(DEPTH)/ipc/ipc.gyp:ipc',
-            '<(DEPTH)/third_party/adobe/flash/flash_player.gyp:flapper_version_h',
             '<(DEPTH)/third_party/re2/re2.gyp:re2',
             '<(DEPTH)/third_party/widevine/cdm/widevine_cdm.gyp:widevine_cdm_version_h',
           ],
           'export_dependent_settings': [
             '<(DEPTH)/chrome/common/extensions/api/api.gyp:chrome_api',
           ],
         }, {  # OS == ios
           'sources/': [
             ['exclude', '^common/child_process_'],
             ['exclude', '^common/chrome_content_client\\.cc$'],
             ['exclude', '^common/chrome_version_info_posix\\.cc$'],
             ['exclude', '^common/common_message_generator\\.cc$'],
             ['exclude', '^common/common_param_traits'],
             ['exclude', '^common/custom_handlers/'],
             ['exclude', '^common/extensions/'],
             ['exclude', '^common/logging_chrome\\.'],
             ['exclude', '^common/media_galleries/'],
             ['exclude', '^common/multi_process_'],
-            ['exclude', '^common/pepper_flash\\.'],
             ['exclude', '^common/profiling\\.'],
             ['exclude', '^common/spellcheck_'],
             ['exclude', '^common/validation_message_'],
             ['exclude', '^common/web_apps\\.'],
             # TODO(ios): Include files here as they are made to work; once
             # everything is online, remove everything below here and just
             # use the exclusions above.
             ['exclude', '\\.(cc|mm)$'],
             ['include', '_ios\\.(cc|mm)$'],
             ['include', '(^|/)ios/'],
             ['include', '^common/chrome_version_info\\.cc$'],
             ['include', '^common/translate'],
             ['include', '^common/zip'],
           ],
           'include_dirs': [
             '<(DEPTH)/breakpad/src',
           ],
         }],
         ['disable_nacl==0', {
           'dependencies': [
             '<(DEPTH)/components/nacl.gyp:nacl_common',
             '<(DEPTH)/ppapi/native_client/src/trusted/plugin/plugin.gyp:nacl_trusted_plugin',
           ],
         }],
+        ['enable_plugins==1', {
+          'dependencies': [
+            '<(DEPTH)/third_party/adobe/flash/flash_player.gyp:flapper_version_h',
+          ],
+          'sources': [
+            'common/pepper_flash.cc',
+            'common/pepper_flash.h',
+            'common/pepper_permission_util.cc',
+            'common/pepper_permission_util.h',
+          ],
+        }],
         ['enable_printing==0', {
           'sources!': [
             'common/print_messages.cc',
             'common/print_messages.h',
           ]
         }, {
           'dependencies': [
             '<(DEPTH)/printing/printing.gyp:printing',
           ],
         }],
@@ skipping 262 matching lines @@
         'common/safe_browsing/csd.proto'
       ],
       'variables': {
         'proto_in_dir': 'common/safe_browsing',
         'proto_out_dir': 'chrome/common/safe_browsing',
       },
       'includes': [ '../build/protoc.gypi' ],
     },
   ],
 }