Add WebRuntimeFeatures::enableDialogElement

Chrome will use this function to enable <dialog> in WebUI as a trial
before exposing to the entire web.

Review URL: https://chromiumcodereview.appspot.com/22518003

git-svn-id: svn://svn.chromium.org/blink/trunk@156369 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Use renderStyle() instead of renderer()->style() in TextControlInnerElement::customStyleForRenderer().

BUG=none

Review URL: https://chromiumcodereview.appspot.com/23137007

git-svn-id: svn://svn.chromium.org/blink/trunk@156370 bbb929c8-8fbe-4397-9dbb-9b2b20218538
drawSystemFocusRing should take canvas transformations into account.

In addition, the accessible rect needs to be applied to ancesetor elements
within the canvas, otherwise their bounding boxes may be clipped.

BUG=261998

Review URL: https://chromiumcodereview.appspot.com/23314002

git-svn-id: svn://svn.chromium.org/blink/trunk@156371 bbb929c8-8fbe-4397-9dbb-9b2b20218538