[Android] Enable remote debugging after rebase to M39

Adjust classes according upstream changes of DevToolsManagerDelegate
and DevToolsHttpHandlerDelegate.
Besides, hardcode webkit revision to generate remote frontend url
due to https://code.google.com/p/chromium/issues/detail?id=425912
The fix itself doesn't work, because the frontend materials online will not change not matter how we patch our blink.

But it will fix this issue partly, by introducing a commit with "git-svn-id" in its commit log, so that when gclient sync runs with my PR in chromium-crosswalk, the WEBKIT_SVN_REVISION will get from that backported commit.

I don't think it's a good approach though, it might be broken by future backport again.