Add structural support for building chrome_browser.gyp on iOS

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 502 matching lines @@
 
         # linux_use_gold_flags: whether to use build flags that rely on gold.
         # On by default for x64 Linux.  Temporarily off for ChromeOS as
         # it failed on a buildbot.
         ['OS=="linux" and chromeos==0', {
           'linux_use_gold_flags%': 1,
         }, {
           'linux_use_gold_flags%': 0,
         }],
 
-        ['OS=="android"', {
+        ['OS=="android" or OS=="ios"', {
           'enable_captive_portal_detection%': 0,
         }, {
           'enable_captive_portal_detection%': 1,
         }],
 
         # Enable Skia UI text drawing incrementally on different platforms.
         # http://crbug.com/105550
         #
         # On Aura, this allows per-tile painting to be used in the browser
         # compositor.
@@ skipping 422 matching lines @@
           }],
           # All Chrome builds have breakpad symbols, but only process the
           # symbols from official builds.
           ['(branding=="Chrome" and buildtype=="Official")', {
             'linux_dump_symbols%': 1,
           }],
         ],
       }],  # os_posix==1 and OS!="mac" and OS!="ios"
       ['OS=="ios"', {
         'disable_nacl%': 1,
+        'enable_background%': 0,
         'enable_gpu%': 0,
         'enable_task_manager%': 0,
         'icu_use_data_file_flag%': 1,
         'use_system_bzip2%': 1,
         'use_system_libxml%': 1,
         'use_system_sqlite%': 1,
 
         # The Mac SDK is set for iOS builds and passed through to Mac
         # sub-builds. This allows the Mac sub-build SDK in an iOS build to be
         # overridden from the command line the same way it is for a Mac build.
@@ skipping 2703 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',
   },
 }