[Android] Add code path for initializing ContentReadbackHandler

ContentReadbackHandler initialization is newly added from chromium
36.0.1985. We need to init it for TextureView path to avoid crash on
destroying.

BUG=https://crosswalk-project.org/jira/browse/XWALK-1887
[TEMP] Publish DEPS for Chromium 36.0.1985.18

Related to XWALK-1894
Merge pull request #164 from hmin/init-readback-handler

[Android] Add code path for initializing ContentReadbackHandler
Merge pull request #163 from halton/update_deps_git

Apply .DEPS.git changes after 1985 branching point.