This is towards closing the perf gap between the MSVC build (which uses link-
time optimization) and Clang (where LTO isn't ready on Windows yet). We did
a study (see bug) to see which non-inlined functions are hit a lot during render
start-up, and which would be inlined during LTO. This should benefit performance
in all builds which currently don't use LTO (Android, Linux, Mac) as well as
the Win/Clang build.

The binary size of chrome_child.dll increases by 2KB with this.

BUG=chromium:728324

Review-Url: https://codereview.chromium.org/2950993002
Cr-Commit-Position: refs/heads/master@{#46191}