This is needed to insulate generated code from blink::protocol namespace
from naming changes that we plan to do in the Great Blink Rename (which
in particular will rename wtf::StringBuilder::find method into Find).

This CL also includes roll of inspector_protocol which starts to
generate code that uses the new StringUtil::find adapter method:
rolling third_party/inspector to 1a7cbe8ba8fa0d622586f549a97c73d9b52efbea

BUG=683447

Review-Url: https://codereview.chromium.org/2675763003
Cr-Commit-Position: refs/heads/master@{#42936}