Update from https://crrev.com/306655

third_party/mesa/mesa.gyp

 # 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.
 
 {
   'variables': {
     'generated_src_dir': 'src/chromium_gensrc',
   },
   'target_defaults': {
     'defines': [
@@ skipping 682 matching lines @@
           4005, 4018, 4065, 4090, 4099, 4291, 4345, 4267,
       ],
       'sources': [
         'src/src/mesa/drivers/common/driverfuncs.c',
         'src/src/mesa/drivers/common/driverfuncs.h',
         'src/src/mesa/drivers/common/meta.c',
         'src/src/mesa/drivers/common/meta.h',
         'src/src/mesa/drivers/osmesa/osmesa.c',
         'src/src/mesa/drivers/osmesa/osmesa.def',
       ],
+      'variables': {
+        'clang_warning_flags_unset': [
+          # Don't warn about string->bool used in asserts.
+          '-Wstring-conversion',
+        ],
+      },
     },
   ],
   'conditions': [
     ['OS=="android"', {
       'targets': [
         {
           # Copies libosmesa.so to the out/$BUILDTYPE/lib/ directory so that
           # the write_ordered_libraries.py script won't assume it to be a
           # system library. This will cause the library to be stripped allowing
           # targets to embed it in the to-be-generated APK.
@@ skipping 12 matching lines @@
                 '<(PRODUCT_DIR)/libosmesa.so',
                 '<(SHARED_LIB_DIR)/libosmesa.so',
               ],
             },
           ],
         },
       ],
     }],
   ],
 }