Update accept_return_character_ for synthetic events too.

Tweak RenderWidgetHostViewAura RETURN key forwarding.
This is a followup fix for http://crrev.com/235194
That prevented forwarding CTRL+M as RETURN for Issue 315547.

This fixes RETURN handling for Win8 Metro Viewer processes.
Metro Viewer's synthetic events should be treated similarly.

BUG=321656,315547
TEST=Win8 Metro Ash Chrome RETURN key should submit web forms.
TBR=nona@chromium.org,jochen@chromium.org

Review URL: https://codereview.chromium.org/79843002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@236478 0039d316-1c4b-4281-b951-d872f2087c98
Add WaitForWriteToFlush to QuicTestClient::SendData.

Merge internal change: 56995306

R=rch@chromium.org

Review URL: https://codereview.chromium.org/79993002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@236479 0039d316-1c4b-4281-b951-d872f2087c98
Update .DEPS.git

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@236480 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 236480
Add a checkstyle rule for Copyright header.

Make sure that a Java file has Chromium copyright  header.
BUG=318404

Review URL: https://codereview.chromium.org/80053002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@236481 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 236481