enable -Wstring-conversion when compiling with clang

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 2786 matching lines @@
               # removed when we change to that.  (This is also why we don't
               # bother fixing all these cases today.)
               '-Wno-unnamed-type-template-args',
               # This (rightfully) complains about 'override', which we use
               # heavily.
               '-Wno-c++11-extensions',
 
               # Warns on switches on enums that cover all enum values but
               # also contain a default: branch. Chrome is full of that.
               '-Wno-covered-switch-default',
+
+              # Warns when a const char[] is converted to bool.
+              '-Wstring-conversion',
             ],
             'cflags!': [
               # Clang doesn't seem to know know this flag.
               '-mfpmath=sse',
             ],
           }],
           ['clang==1 and clang_use_chrome_plugins==1', {
             'cflags': [
               '<@(clang_chrome_plugins_flags)',
             ],
@@ skipping 564 matching lines @@
 
                 # Don't die on dtoa code that uses a char as an array index.
                 # This is required solely for base/third_party/dmg_fp/dtoa.cc.
                 '-Wno-char-subscripts',
                 # Clang spots more unused functions.
                 '-Wno-unused-function',
 
                 # Warns on switches on enums that cover all enum values but
                 # also contain a default: branch. Chrome is full of that.
                 '-Wno-covered-switch-default',
+
+                # Warns when a const char[] is converted to bool.
+                '-Wstring-conversion',
               ],
               'OTHER_CPLUSPLUSFLAGS': [
                 # gnu++11 instead of c++11 so that __ANSI_C__ doesn't get
                 # defined.  (Else e.g. finite() in base/float_util.h needs to
                 # be isfinite() which doesn't exist on the android bots.)
                 # typeof() is also disabled in c++11 (but we could use
                 # decltype() instead).
                 # TODO(thakis): Use CLANG_CXX_LANGUAGE_STANDARD instead once all
                 # bots use xcode 4 -- http://crbug.com/147515).
                 # TODO(thakis): Eventually switch this to c++11 instead of
@@ skipping 645 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',
   },
 }