Add compiler/linker flags to optimize WinRT release builds
Add compiler/linker flags to optimize WinRT release builds

This reduces the WinRT binary sizes by up to 500KB.

BUG=angleproject:1250

Change-Id: I2ce0e9597c49515fe4b414f105b03785d6ce132f
Reviewed-on: https://chromium-review.googlesource.com/317595
Tryjob-Request: Austin Kinross <4e7ea65cff3a7294234757a0f33c94811ce2f382@microsoft.com>
Reviewed-by: Geoff Lang <b6fc25fe0362055230985c05cbfa8adb741ccc0f@chromium.org>
Reviewed-by: Jamie Madill <7e492b4f1c8458024932de3ba475cbf015424c30@chromium.org>
Tested-by: Jamie Madill <7e492b4f1c8458024932de3ba475cbf015424c30@chromium.org>

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