All the counters, trace events and runtime call stats roughly create a 30%
overhead when calling into the runtime. This CL factors out the counters into
separate non-inlined functions. This way we can reduce the overhead to a
minimum and still have some useful stats without a compile-time flag.

BUG=chromium:596055
LOG=n

Review URL: https://codereview.chromium.org/1868513002

Cr-Commit-Position: refs/heads/master@{#35308}