Revert 153092 - Turn on warnings as errors for (most) third_party code on Windows

build/common.gypi

Index: build/common.gypi
===================================================================
--- build/common.gypi	(revision 153221)
+++ build/common.gypi	(working copy)
@@ -710,14 +710,6 @@
     # to get incremental linking to be faster in debug builds.
     'incremental_chrome_dll%': '0',
 
-    # The default settings for third party code for treating
-    # warnings-as-errors. Ideally, this would not be required, however there
-    # is some third party code that takes a long time to fix/roll. So, this
-    # flag allows us to have warnings as errors in general to prevent
-    # regressions in most modules, while working on the bits that are
-    # remaining.
-    'win_third_party_warn_as_error%': 'true',
-
     # This is the location of the sandbox binary. Chrome looks for this before
     # running the zygote process. If found, and SUID, it will be used to
     # sandbox the zygote process and, thus, all renderer processes.
@@ -1685,7 +1677,7 @@
             'msvs_settings': {
               'VCCLCompilerTool': {
                 'WarningLevel': '3',
-                'WarnAsError': '<(win_third_party_warn_as_error)',
+                'WarnAsError': 'false', # TODO(maruel): Enable it.
                 'Detect64BitPortabilityProblems': 'false',
               },
             },