Fix host gcc version detection for android webview.

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 1437 matching lines @@
         ],
       }, {
         'binutils_version%': 0,
       }],
       # The version of GCC in use, set later in platforms that use GCC and have
       # not explicitly chosen to build with clang. Currently, this means all
       # platforms except Windows, Mac and iOS.
       # TODO(glider): set clang to 1 earlier for ASan and TSan builds so that
       # it takes effect here.
       ['os_posix==1 and OS!="mac" and OS!="ios" and clang==0 and asan==0 and lsan==0 and tsan==0 and msan==0', {
-        'host_gcc_version%': '<!pymod_do_main(compiler_version host compiler)',
         'conditions': [
           ['OS=="android"', {
             # We directly set the gcc versions since we know what we use.
             'gcc_version%': 48,
           }, {
             'gcc_version%': '<!pymod_do_main(compiler_version target compiler)',
           }],
+          ['android_webview_build==1', {
+            # Android WebView uses a hermetic toolchain even for host, so set it
+            # manually here.
+            'conditions': [
+              ['host_os=="mac"', {
+                'host_gcc_version%': 42,
+              }, { # linux
+                'host_gcc_version%': 46,
+              }],
+            ],
+          }, {  # android_webview_build!=1
+            'host_gcc_version%': '<!pymod_do_main(compiler_version host compiler)',
+          }],
         ],
       }, {
         'host_gcc_version%': 0,
         'gcc_version%': 0,
       }],
       ['OS=="win" and "<!pymod_do_main(dir_exists <(windows_sdk_default_path))"=="True"', {
         'windows_sdk_path%': '<(windows_sdk_default_path)',
       }, {
         'windows_sdk_path%': 'C:/Program Files (x86)/Windows Kits/8.0',
       }],
@@ skipping 3889 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',
   },
 }