DeviceOrientationDispatcher: no orientation updates equal to lastOrientation().

The DeviceOrientationDispatcher, which implements WebDeviceOrientationClient,
must not send orientation updates that are equal to its lastOrientation().
This can happen when the client is stopped and then started again.

BUG=44654
TEST=Manual

Review URL: http://codereview.chromium.org/3104038

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@57650 0039d316-1c4b-4281-b951-d872f2087c98
2 files changed