Allow Preroll() call on VideoRendererImpl without a Flush().

This is the first patch in a sequence of changes to enable Pipeline
to properly manage underflows. This change allows the VideoRendererImpl
to be prerolled in non-seek situations.

BUG=144683
TEST=VideoRendererImplTest.Rebuffer, VideoRendererImplTest.Rebuffer_AlreadyHaveEnoughFrames

Review URL: https://codereview.chromium.org/89673002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@238513 0039d316-1c4b-4281-b951-d872f2087c98
Prevent upscaling in desktop capture.

The previous CL landed (r238359) is missing a size check to prevent upscaling
in desktop capture. The correct logic should be to use native resolution
if both maxWidth and maxHeight are no smaller than source dimensions, and
to compute letterbox region if otherwise.

BUG=324923
TEST=trybot, Chrome OS feedback screen captures in native resolution
R=sergeyu@chromium.org
TBR=wjia@chromium.org

Review URL: https://codereview.chromium.org/103253003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@238514 0039d316-1c4b-4281-b951-d872f2087c98
Fix popup crash on ChromeOS.

The popup collection was not handling correctly the case where it tells
the message center to mark its popups read, causing a NOTREACHED in
observer list.

BUG=324142

Review URL: https://codereview.chromium.org/99543003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@238515 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 238515
Disable page_cycler.typical_25 on windows, and session_restore.cold.typical_25 on linux.

NOTRY=true
BUG=273986, 325479

Review URL: https://codereview.chromium.org/103153002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@238516 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 238516