[android_webview] Suppress warning for Android build.

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 3834 matching lines @@
                   # can redefine it later to be 2 for chromium code and unset
                   # for third party code. This works because cflags are added
                   # before defines.
                   '-U_FORTIFY_SOURCE',
                   # Disable any additional warnings enabled by the Android build system but which
                   # chromium does not build cleanly with (when treating warning as errors).
                   # Things that are part of -Wextra:
                   '-Wno-extra', # Enabled by -Wextra, but no specific flag
                   '-Wno-ignored-qualifiers',
                   '-Wno-type-limits',
+                  '-Wno-unused-but-set-variable',
                 ],
                 'cflags_cc': [
                   # Other things unrelated to -Wextra:
                   '-Wno-non-virtual-dtor',
                   '-Wno-sign-promo',
                 ],
               }],
               ['android_webview_build==1', {
                 'target_conditions': [
                   ['chromium_code==0', {
@@ skipping 1045 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',
   },
 }