Implement basic classes for HPACK (HTTP/2 compression)

Create HpackEncodingContext, HpackHeaderTable, and HpackEntry classes,
which are based on the draft
http://tools.ietf.org/html/draft-ietf-httpbis-header-compression-04 .

Implement some basic tests.

This implementation is based on
https://github.com/akalin-chromium/httpbis-header-compression and
https://codereview.chromium.org/22074002/ (which was based on an
earlier draft).

This lands server change 55803359 by akalin.

R=akalin@chromium.org

Review URL: https://codereview.chromium.org/138243003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@245162 0039d316-1c4b-4281-b951-d872f2087c98
Invokes SchedulePaint when animation ended to repaint the background.

BUG=334461
R=xiyuan@chromium.org
TEST=manually

Review URL: https://codereview.chromium.org/138273006

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@245163 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 245163
Files.app: Add a drive sync error event to the fileBrowserPrivate API.

Previously no API is provided to report drive sync errors to JavaScript side.
This CL adds the API and colllecs erros by using OperationObserver.

BUG=260510

Review URL: https://codereview.chromium.org/137903002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@245164 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 245164