Split bundle generation steps so that API registration is generated in browser, not common.

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 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)/skia/skia.gyp:skia',
+        '<(DEPTH)/sync/sync.gyp:sync',
+        '<(DEPTH)/ui/accessibility/accessibility.gyp:ax_gen',
+      ],
+      'conditions': [
+        ['OS != "ios" and OS != "android"', {
+          'dependencies': [
+            '<(DEPTH)/components/components.gyp:copresence_proto',
+          ],
+        }],
+        ['chromeos==1', {
+          'dependencies': [
+            '<(DEPTH)/chrome/chrome.gyp:drive_proto',
+          ],
+        }],
+      ],
+    },
+  ],
+}