Remove GpuChannelHostFactory::GetShutDownEvent().

I'd like to add GetShutDownEvent() to RenderThread. However, that would cause
RenderThreadImpl to have two base classes specify that method, which is pretty
weird.

This removes GpuChannelHostFactory::GetShutDownEvent() and provides the
shutdown event in the GpuChannelHost constructor instead.

BUG=

Review URL: https://codereview.chromium.org/181413003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@254515 0039d316-1c4b-4281-b951-d872f2087c98
webkit: Correctly handle |has_more| parameter in FileSystemDirURLRequestJob

What should be done when has_more==false is not calling ReadDirectory again,
just waiting for the following results.

BUG=347900

Review URL: https://codereview.chromium.org/176863003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@254517 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 254515
SVN changes up to revision 254517