Remove threading primitives from ParseHTMLOnMainThread

This patch removes locks from ParsedChunkQueue, and use
of crossThreadBind in HTMLDocumentParser/BackgroundHTMLParser,
which introduces unecessary copies if we're not actually crossing
threads.

BUG=627198

Review-Url: https://codereview.chromium.org/2134323002
Cr-Commit-Position: refs/heads/master@{#405139}
6 files changed