Add GN Build file for extensions_common target.

content/renderer/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/features.gni")
 import("//build/config/ui.gni")
 import("//content/renderer/renderer.gni")
 
 source_set("renderer") {
   # Only targets in the content tree can depend directly on this target.
@@ skipping 56 matching lines @@
     sources += [
       "external_popup_menu.cc",
       "external_popup_menu.h",
     ]
   }
 
   if (is_android) {
     sources -= [
       "accessibility/renderer_accessibility_focus_only.cc",
       "media/audio_decoder.cc",
-      "media/filter_helpers.cc",
       "media/webmediaplayer_impl.cc",
     ]
     sources += [
       "external_popup_menu.cc",
       "external_popup_menu.h",
     ]
 
     # Add back the Linux file which Android shares.
     set_sources_assignment_filter([])
     sources += [
@@ skipping 74 matching lines @@
         "media/webrtc/video_destination_handler.h",
       ]
     }
   }
 
   if (enable_plugins && enable_webrtc) {
     sources += rebase_path(
         content_renderer_gypi_values.private_renderer_plugin_webrtc_sources,
         ".", "//content")
   }
-
-  if (!enable_pepper_cdms) {
-    sources -= [
-      "renderer/media/crypto/ppapi_decryptor.cc",
-      "renderer/media/crypto/ppapi_decryptor.h",
-    ]
-  }
 }