Restore accidentally deleted comment

BUILD.gn

 # Copyright 2014 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.
 
 import("//third_party/icu/config.gni")
 
 if (is_android) {
   import("//build/config/android/rules.gni")
 }
 
@@ skipping 55 matching lines @@
     # Will cut down the code size.
     "U_CHARSET_IS_UTF8=1",
   ]
 
   if (is_win) {
     # Disable some compiler warnings.
     cflags += [
       "/wd4005",  # Macro redefinition.
       "/wd4068",  # Unknown pragmas.
       "/wd4267",  # Conversion from size_t on 64-bits.
+      # http://bugs.icu-project.org/trac/ticket/12821
       "/wd4333",  # Right shift by too large amount.
     ]
   } else if (is_linux || is_android) {
     cflags += [
       "-Wno-unused-function",
     ]
   }
   if (is_clang) {
     cflags += [
       # ICU uses its own deprecated functions.
@@ skipping 938 matching lines @@
       }
     }
 
     source_set("icudata") {
       sources = [ "$data_assembly" ]
       defines = [ "U_HIDE_DATA_SYMBOL" ]
       deps = [ ":make_data_assembly", ]
     }
   }
 }