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- short -> int16_t except layout_theme_mac.mm.
- int -> uint8_t, short -> float in layout_theme_mac.mm.
- Reference: https://google.github.io/styleguide/cppguide.html#Integer_Types

Bug: 929985
Change-Id: I2d8beb79720350f14c99f82a8d53acdd5833e99f
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1501773Reviewed-by: Kentaro Hara <haraken@chromium.org>
Commit-Queue: Miyoung Shin <myid.shin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#637914}