Create new app_shell.gyp for app_shell targets.

extensions/extensions.gyp

Index: extensions/extensions.gyp
diff --git a/extensions/extensions.gyp b/extensions/extensions.gyp
index c2b8b26728c9fa1f6b270bf975fff81cf69bdb31..f31703582a41694980ee304b80a39fde70fe4980 100644
--- a/extensions/extensions.gyp
+++ b/extensions/extensions.gyp
@@ -11,6 +11,7 @@
       'target_name': 'extensions_common',
       'type': 'static_library',
       'dependencies': [
+        'common/api/api.gyp:extensions_api',
         '../third_party/re2/re2.gyp:re2',
         # TODO(benwells): figure out what to do with the api target and
         # api resources compiled into the chrome resource bundle.
@@ -18,7 +19,6 @@
         '../chrome/chrome_resources.gyp:chrome_resources',
         # TODO(jamescook|derat): Pull strings into extensions module.
         '../chrome/chrome_resources.gyp:chrome_strings',
-        '../chrome/common/extensions/api/api.gyp:chrome_api',
         '../components/components.gyp:url_matcher',
         '../content/content.gyp:content_common',
       ],
@@ -183,7 +183,7 @@
         'common/api/api.gyp:extensions_api',
         # TODO(jamescook|derat): Pull strings into extensions module.
         '../chrome/chrome_resources.gyp:chrome_strings',
-        '../chrome/common/extensions/api/api.gyp:chrome_api',
+        '../components/components.gyp:keyed_service_content',
         '../content/content.gyp:content_browser',
         '../skia/skia.gyp:skia',
         '../third_party/leveldatabase/leveldatabase.gyp:leveldatabase',