Make all base targets build on Win64

base/base.gyp

Index: base/base.gyp
===================================================================
--- base/base.gyp	(revision 175573)
+++ base/base.gyp	(working copy)
@@ -270,6 +270,12 @@
             '../build/linux/system.gyp:gtk',
           ],
         }],
+        ['OS == "win"', {
+          # TODO(jschuh): crbug.com/167187 fix size_t to int truncations.
+          'msvs_disabled_warnings': [
+            4267,
+          ],
+        }],
       ],
       'export_dependent_settings': [
         'base',
@@ -708,6 +714,10 @@
             'threading/worker_pool_posix_unittest.cc',
             'message_pump_libevent_unittest.cc',
           ],
+          # TODO(jschuh): crbug.com/167187 fix size_t to int truncations.
+          'msvs_disabled_warnings': [
+            4267,
+          ],
         }, {  # OS != "win"
           'dependencies': [
             '../third_party/libevent/libevent.gyp:libevent'