Remove no_size_t_to_int_warning in //ui/message_center

Bug: 167187
Change-Id: Ie7b6c5714567d8486fcc6ce16f17cc418ca6ac30
Reviewed-on: https://chromium-review.googlesource.com/c/1393332Reviewed-by: Avi Drissman <avi@chromium.org>
Commit-Queue: Avi Drissman <avi@chromium.org>
Cr-Commit-Position: refs/heads/master@{#619463}

ui/message_center/BUILD.gn

@@ -55,12 +55,7 @@ jumbo_component("message_center") {
       "//ui/resources",
     ]
 
-    configs += [
-      "//build/config:precompiled_headers",
-
-      # TODO(jschuh): crbug.com/167187 fix size_t to int truncations.
-      "//build/config/compiler:no_size_t_to_int_warning",
-    ]
+    configs += [ "//build/config:precompiled_headers" ]
     sources = [
       "lock_screen/empty_lock_screen_controller.cc",
       "lock_screen/empty_lock_screen_controller.h",