Fix more disabled MSVC warnings, base/ edition.

Mostly this fixes cases of "possible value truncation", usually by inserting
explicit typecasts.

BUG=81439
TEST=none

Review URL: https://codereview.chromium.org/596103002

Cr-Commit-Position: refs/heads/master@{#297723}


CrOS-Libchrome-Original-Commit: 9cf9b94a63dec7653bb48bac948deb4008b532c8
20 files changed
tree: f0bb5927663ad1925562fc41bf5e2e41711d6519
  1. base/
  2. build/
  3. components/
  4. dbus/
  5. device/
  6. ipc/
  7. mojo/
  8. testing/
  9. third_party/
  10. ui/