Increase warning level to 4 on Visual Studio

build/common.gypi

 # Copyright (c) 2011 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 740 matching lines @@
           [ 'OS=="win"', {
             'defines': [
               '_CRT_SECURE_NO_DEPRECATE',
               '_CRT_NONSTDC_NO_WARNINGS',
               '_CRT_NONSTDC_NO_DEPRECATE',
               '_SCL_SECURE_NO_DEPRECATE',
             ],
             'msvs_disabled_warnings': [4800],
             'msvs_settings': {
               'VCCLCompilerTool': {
-                'WarnAsError': 'false',
+                'WarningLevel': '3',
+                'WarnAsError': 'false', # TODO(maruel): Enable it.
                 'Detect64BitPortabilityProblems': 'false',
               },
             },
           }],
           [ 'OS=="mac"', {
             'xcode_settings': {
               'GCC_TREAT_WARNINGS_AS_ERRORS': 'NO',
               'WARNING_CFLAGS!': ['-Wall', '-Wextra'],
             },
           }],
@@ skipping 741 matching lines @@
               '_SECURE_ATL',
             ],
           }],
         ],
         'msvs_system_include_dirs': [
           '<(DEPTH)/third_party/platformsdk_win7/files/Include',
           '<(DEPTH)/third_party/directxsdk/files/Include',
           '$(VSInstallDir)/VC/atlmfc/include',
         ],
         'msvs_cygwin_dirs': ['<(DEPTH)/third_party/cygwin'],
-        'msvs_disabled_warnings': [4351, 4396, 4503, 4819],
+        'msvs_disabled_warnings': [4351, 4396, 4503, 4819,
+          # TODO(maruel): These warnings are level 4. They will be slowly
+          # removed as code is fixed.
+          4100, 4121, 4125, 4127, 4130, 4131, 4189, 4201, 4238, 4244, 4245,
+          4310, 4355, 4428, 4481, 4505, 4510, 4512, 4530, 4610, 4611, 4701,
+          4702, 4706,
+        ],
         'msvs_settings': {
           'VCCLCompilerTool': {
             'MinimalRebuild': 'false',
             'BufferSecurityCheck': 'true',
             'EnableFunctionLevelLinking': 'true',
             'RuntimeTypeInfo': 'false',
-            'WarningLevel': '3',
+            'WarningLevel': '4',
             'WarnAsError': 'true',
             'DebugInformationFormat': '3',
             'conditions': [
               ['msvs_multi_core_compile', {
                 'AdditionalOptions': ['/MP'],
               }],
               ['MSVS_VERSION=="2005e"', {
                 'AdditionalOptions': ['/w44068'], # Unknown pragma to 4 (ATL)
               }],
               ['component=="shared_library"', {
@@ skipping 158 matching lines @@
     # and therefore SYMROOT, needs to be set at the project level.
     'SYMROOT': '<(DEPTH)/xcodebuild',
   },
 }
 
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