clang/win: Disable -Wunused-local-typedef for now.

BUG=411648,82385
TBR=hans@chromium.org

Review URL: https://codereview.chromium.org/550713002

Cr-Original-Commit-Position: refs/heads/master@{#293635}
Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: 5897272424994925428a8d1d9a32c5199efe09c8

common.gypi

@@ -5501,6 +5501,7 @@
                   '-Wno-unused-private-field',
                   '-Wno-unused-value',
                   '-Wno-unused-variable',
+                  '-Wno-unused-local-typedef',  # http://crbug.com/411648
                 ],
               },
             }],