Remove worker process related codes from ContentBrowserClient.

BUG=327256

Review URL: https://codereview.chromium.org/468033002

Cr-Commit-Position: refs/heads/master@{#290139}
git-svn-id: svn://svn.chromium.org/chrome/trunk/src@290139 0039d316-1c4b-4281-b951-d872f2087c98
12 files changed