Fixing remaining VC++ 2015 64-bit build breaks

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 3116 matching lines @@
             ],
           }],
           [ 'OS=="win"', {
             'defines': [
               '_CRT_SECURE_NO_DEPRECATE',
               '_CRT_NONSTDC_NO_WARNINGS',
               '_CRT_NONSTDC_NO_DEPRECATE',
               '_SCL_SECURE_NO_DEPRECATE',
             ],
             'msvs_disabled_warnings': [
+              # forcing value to bool 'true' or 'false' (performance warning)
               4800,
             ],
             'msvs_settings': {
               'VCCLCompilerTool': {
                 'WarningLevel': '3',
                 'WarnAsError': 'true',
                 'Detect64BitPortabilityProblems': 'false',
               },
             },
             'conditions': [
@@ skipping 2460 matching lines @@
                   },
                 ],
               ],
             },
           ],
           ['msvs_xtree_patched!=1', {
             # If xtree hasn't been patched, then we disable C4702. Otherwise,
             # it's enabled. This will generally only be true for system-level
             # installed Express users.
             'msvs_disabled_warnings': [
-              4702,
+              4702, # unreachable code
             ],
           }],
         ],
         'msvs_system_include_dirs': [
           '<(windows_sdk_path)/Include/shared',
           '<(windows_sdk_path)/Include/um',
           '<(windows_sdk_path)/Include/winrt',
           '$(VSInstallDir)/VC/atlmfc/include',
         ],
         'msvs_cygwin_shell': 0,
@@ skipping 63 matching lines @@
           4512, # Assignment operator could not be generated
           4610, # Object can never be instantiated
           4838, # Narrowing conversion. Doesn't seem to be very useful.
           4995, # 'X': name was marked as #pragma deprecated
           4996, # 'X': was declared deprecated (for GetVersionEx).
 
           # These are variable shadowing warnings that are new in VS2015. We
           # should work through these at some point -- they may be removed from
           # the RTM release in the /W4 set.
           4456, 4457, 4458, 4459,
+
+          # The x64 builds with VS 2015 trigger hundreds of warnings about
+          # pointer truncation but these are all or virtually all by design, and
+          # therefore not worth fixing individually. The C4311 warnings are
+          # particularly common in libxml. The C4312 warnings are particularly
+          # common in libxml and v8.
+          4311, # type cast: pointer truncation from pointer to smaller integer

[Will Harris, 2015/11/10 23:01:30]

as per pkasting suggestion, please try and scope these down to just the areas
required e.g. libxml and v8 rather than entirety of Chrome

[brucedawson, 2015/11/11 01:09:04]

I'll try that, and see how messy it gets.

+          4312, # type cast: conversion from integer to larger pointer
         ],
         'msvs_settings': {
           'VCCLCompilerTool': {
             'AdditionalOptions': ['/MP'],
             'MinimalRebuild': 'false',
             'BufferSecurityCheck': 'true',
             'EnableFunctionLevelLinking': 'true',
             'RuntimeTypeInfo': 'false',
             'WarningLevel': '4',
             'WarnAsError': 'true',
@@ skipping 597 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',
   },
 }