clang/win: Don't pass -Wno-inconsistent-missing-override twice.

build/config/compiler/BUILD.gn

Index: build/config/compiler/BUILD.gn
diff --git a/build/config/compiler/BUILD.gn b/build/config/compiler/BUILD.gn
index 40e6eef4b6942e065b96e4751561a8f0c89019a8..33ead6b4b6290addb384e05d2c5deea3ce9d1ddc 100644
--- a/build/config/compiler/BUILD.gn
+++ b/build/config/compiler/BUILD.gn
@@ -830,7 +830,6 @@ if (is_win) {
       "-Wno-unused-value",
       "-Wno-unused-variable",
       "-Wno-unused-local-typedef",  # http://crbug.com/411648
-      "-Wno-inconsistent-missing-override",  #http://crbug.com/428099
     ]
   }
 } else {
@@ -937,7 +936,7 @@ if (is_clang) {
   if (!is_nacl) {
     # Flags NaCl does not recognize.
     default_warning_flags += [
-      # TODO(hans): Get this cleaned up.
+      # TODO(hans): Get this cleaned up, http://crbug.com/428099
       "-Wno-inconsistent-missing-override",
     ]
   }