Patch 2: Added a preprocessor flag for platform spellcheck.

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 549 matching lines @@
       # Only evaluated if cld_version == 2 or if building the CLD2 dynamic data
       # tool explicitly.
       # See third_party/cld_2/cld_2.gyp for more information.
       #   0: Small tables, lower accuracy
       #   2: Large tables, high accuracy
       'cld2_table_size%': 2,
 
       # Enable spell checker.
       'enable_spellcheck%': 1,
 
+      # Use the operating system spellchecker, e.g. NSSpellChecker on Mac or
+      # SpellCheckerSession on Android.
+      'use_platform_spellchecker%': 0,
+
       # Webrtc compilation is enabled by default. Set to 0 to disable.
       'enable_webrtc%': 1,
 
       # Media router support is enabled by default. Set to 0 to disable.
       'enable_media_router%': 1,
 
       # Enables use of the session service, which is enabled by default.
       # Support for disabling depends on the platform.
       'enable_session_service%': 1,
 
@@ skipping 232 matching lines @@
           'remoting%': 0,
           'arm_neon%': 0,
           'arm_neon_optional%': 1,
           'native_memory_pressure_signals%': 1,
           'enable_basic_printing%': 1,
           'enable_print_preview%': 0,
           'enable_task_manager%':0,
           'video_hole%': 1,
         }],
 
+        # OSX has a built-in spellchecker can be utilized.
+        ['OS=="mac"', {
+          'use_platform_spellchecker%': 1,
+        }],
+
         # Android OS includes support for proprietary codecs regardless of
         # building Chromium or Google Chrome. We also ship Google Chrome and
         # Chromecast with proprietary codecs.
         ['OS=="android" or branding=="Chrome" or chromecast==1', {
           'proprietary_codecs%': 1,
         }, {
           'proprietary_codecs%': 0,
         }],
 
         ['OS=="mac" or OS=="ios"', {
@@ skipping 355 matching lines @@
     'enable_background%': '<(enable_background)',
     'linux_use_bundled_gold%': '<(linux_use_bundled_gold)',
     'linux_use_bundled_binutils%': '<(linux_use_bundled_binutils)',
     'linux_use_gold_flags%': '<(linux_use_gold_flags)',
     'linux_use_debug_fission%': '<(linux_use_debug_fission)',
     'use_canvas_skia%': '<(use_canvas_skia)',
     'test_isolation_mode%': '<(test_isolation_mode)',
     'enable_basic_printing%': '<(enable_basic_printing)',
     'enable_print_preview%': '<(enable_print_preview)',
     'enable_spellcheck%': '<(enable_spellcheck)',
+    'use_platform_spellchecker%': '<(use_platform_spellchecker)',
     'enable_google_now%': '<(enable_google_now)',
     'cld_version%': '<(cld_version)',
     'cld2_table_size%': '<(cld2_table_size)',
     'enable_captive_portal_detection%': '<(enable_captive_portal_detection)',
     'disable_file_support%': '<(disable_file_support)',
     'disable_ftp_support%': '<(disable_ftp_support)',
     'use_icu_alternatives_on_android%': '<(use_icu_alternatives_on_android)',
     'enable_task_manager%': '<(enable_task_manager)',
     'sas_dll_path%': '<(sas_dll_path)',
     'wix_path%': '<(wix_path)',
@@ skipping 1771 matching lines @@
         'defines': ['ENABLE_BASIC_PRINTING=1'],
       }],
       ['enable_print_preview==1', {
         # Enable printing with print preview.
         # Can be defined without ENABLE_BASIC_PRINTING.
         'defines': ['ENABLE_PRINT_PREVIEW=1'],
       }],
       ['enable_spellcheck==1', {
         'defines': ['ENABLE_SPELLCHECK=1'],
       }],
+      ['use_platform_spellchecker', {
+        'defines': ['USE_PLATFORM_SPELLCHECKER=1'],
+      }],
       ['enable_captive_portal_detection==1', {
         'defines': ['ENABLE_CAPTIVE_PORTAL_DETECTION=1'],
       }],
       ['enable_app_list==1', {
         'defines': ['ENABLE_APP_LIST=1'],
       }],
       ['enable_settings_app==1', {
         'defines': ['ENABLE_SETTINGS_APP=1'],
       }],
       ['disable_file_support==1', {
@@ skipping 3199 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',
   },
 }