Add missing dependencies to the GYP build.

chrome/browser/extensions/api/api_registration.gyp

 # 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.
 
 {
   'targets': [
     {
       # GN version: //chrome/browser/extensions/api:api_registration
       'target_name': 'chrome_api_registration',
       'type': 'static_library',
       # TODO(jschuh): http://crbug.com/167187 size_t -> int
       'msvs_disabled_warnings': [ 4267 ],
       'includes': [
         '../../../../build/json_schema_bundle_registration_compile.gypi',
         '../../../common/extensions/api/schemas.gypi',
       ],
       'dependencies': [
         '<(DEPTH)/chrome/common/extensions/api/api.gyp:chrome_api',
+
+        # Different APIs include headers from these targets.
+        "<(DEPTH)/content/content.gyp:content_browser",
+
         # Different APIs include some headers from chrome/common that in turn
         # include generated headers from these targets.
         # TODO(brettw) this should be made unnecessary if possible.
         '<(DEPTH)/components/components.gyp:component_metrics_proto',
         '<(DEPTH)/components/components.gyp:copresence_proto',
         '<(DEPTH)/skia/skia.gyp:skia',
         '<(DEPTH)/sync/sync.gyp:sync',
         '<(DEPTH)/ui/accessibility/accessibility.gyp:ax_gen',
       ],
       'conditions': [
         ['chromeos==1', {
           'dependencies': [
             '<(DEPTH)/chrome/chrome.gyp:drive_proto',
           ],
         }],
       ],
     },
   ],
 }