Update docs for CLD2 dynamic data

build/common.gypi

 # Copyright (c) 2012 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.
 
 # IMPORTANT:
 # Please don't directly include this file if you are building via gyp_chromium,
 # since gyp_chromium is automatically forcing its inclusion.
 {
   # Variables expected to be overriden on the GYP command line (-D) or by
   # ~/.gyp/include.gypi.
@@ skipping 445 matching lines @@
       #   1: Medium tables, medium accuracy
       #   2: Large tables, high accuracy
       'cld2_table_size%': 2,
 
       # The data acquisition mode for CLD2. Possible values are:
       #   static:     CLD2 data is statically linked to the executable.
       #   standalone: CLD2 data is provided in a standalone file that is
       #               bundled with the executable.
       #   component:  CLD2 data is provided as a Chrome "component" and is
       #               downloaded via the component updater.
+      #
+      # For more information on switching the CLD2 data source, see:
+      #   https://sites.google.com/a/chromium.org/dev/developers/how-tos/compact-language-detector-cld-data-source-configuration
       'cld2_data_source': 'static',
 
       # Enable spell checker.
       'enable_spellcheck%': 1,
 
       # Webrtc compilation is enabled by default. Set to 0 to disable.
       'enable_webrtc%': 1,
 
       # Enables use of the session service, which is enabled by default.
       # Support for disabling depends on the platform.
@@ skipping 5035 matching lines @@
     # settings in target dicts.  SYMROOT is a special case, because many other
     # Xcode variables depend on it, including variables such as
     # PROJECT_DERIVED_FILE_DIR.  When a source group corresponding to something
     # like PROJECT_DERIVED_FILE_DIR is added to a project, in order for the
     # files to appear (when present) in the UI as actual files and not red
     # red "missing file" proxies, the correct path to PROJECT_DERIVED_FILE_DIR,
     # and therefore SYMROOT, needs to be set at the project level.
     'SYMROOT': '<(DEPTH)/xcodebuild',
   },
 }