Android: use grit target platform instead of define.

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 1475 matching lines @@
         'grit_defines': ['-D', 'use_titlecase'],
       }],
       ['use_third_party_translations==1', {
         'grit_defines': ['-D', 'use_third_party_translations'],
         'locales': [
           'ast', 'bs', 'ca@valencia', 'en-AU', 'eo', 'eu', 'gl', 'hy', 'ia',
           'ka', 'ku', 'kw', 'ms', 'ug'
         ],
       }],
       ['OS=="android"', {
-        'grit_defines': ['-D', 'android',
+        'grit_defines': ['-t', 'android',
                          '-E', 'ANDROID_JAVA_TAGGED_ONLY=true'],
       }],
       ['OS=="mac"', {
         'grit_defines': ['-D', 'scale_factors=2x'],
       }],
       ['OS == "ios"', {
         'grit_defines': [
           # define for iOS specific resources.
           '-D', 'ios',
           # iOS uses a whitelist to filter resources.
@@ skipping 2932 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',
   },
 }