Remove unnecessary include of wtf/CPU.h from a few files.

BUG=none

Review URL: https://chromiumcodereview.appspot.com/23463041

git-svn-id: svn://svn.chromium.org/blink/trunk@157924 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Positioning should account for the grid items' margins

This change just adds the margin before / start to the grid items'
positions. In order to get consistent behavior, we now have to call
findChildLogicalPosition after layout (that's where we compute the
margins).

Also removed some FIXMEs that were handled in the code.

Review URL: https://chromiumcodereview.appspot.com/23463036

git-svn-id: svn://svn.chromium.org/blink/trunk@157925 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Remove the logic that we evict "ownerless" webgl context first.

Because some "ownerless" contexts could be very active whereas "owned" context could be stale for a while.

BUG=290482
TEST=webgl conformance test: rendering/multisample-corruption.html

Review URL: https://chromiumcodereview.appspot.com/23691072

git-svn-id: svn://svn.chromium.org/blink/trunk@157926 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Fix aspect ratio of <video> in fullscreen mode.

For video element, if the ObjectFitPosition flag is not enabled, we use ObjectFitContain by default.

BUG=282484
TEST=<video> aspect ratio in fullscreen mode is correct with or without
ObjectFitPosition flag enabled.

Review URL: https://chromiumcodereview.appspot.com/23496038

git-svn-id: svn://svn.chromium.org/blink/trunk@157927 bbb929c8-8fbe-4397-9dbb-9b2b20218538