Disable warning 4251 for ShaderVars.h. Exporting STL classes from a DLL produces a warning on MSVS. This warning would only show up for component builds. Change-Id: I1bd9b820a45c04f92b0278d7018507d6a2bc7936 Reviewed-on: https://chromium-review.googlesource.com/251704 Reviewed-by: Jamie Madill <jmadill@chromium.org> Tested-by: Jamie Madill <jmadill@chromium.org>