Put console.time into a separate trace event category.

In rendering benchmarks we want to only capture trace events that are
required for the benchmark. console.time is used frequently, but everything
else from the 'webkit' category is not. Putting console.time into a separate
category 'webkit.console' will reduce overhead and make trace buffer overflows
less likely.

R=jamesr@chromium.org, nduca@chromium.org, tonyg@chromium.org
BUG=264308

Review URL: https://chromiumcodereview.appspot.com/23848006

git-svn-id: svn://svn.chromium.org/blink/trunk@157377 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Make WebFileSystemCallbacks not self-destruct, deprecate AsyncFileSystem

The last piece of cleanup.

Depends on chromium-side change (with ifdef):
https://codereview.chromium.org/23762002/

BUG=257349

Review URL: https://chromiumcodereview.appspot.com/23704004

git-svn-id: svn://svn.chromium.org/blink/trunk@157378 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Made pad-gesture-fling layout test deterministic

BUG=261277

Review URL: https://chromiumcodereview.appspot.com/23711005

git-svn-id: svn://svn.chromium.org/blink/trunk@157379 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Revert "Ignore should-scroll-on-main-thread if main frame is not scrollable"

Turns out FrameView::isScrollable can sometimes crash. Reverting this change
while I try and figure out why.

This reverts commit 1a3edc542e31626a9b46ae2b18eb227c7031f3d6.

TBR=jamesr@chromium.org
BUG=280679

Review URL: https://chromiumcodereview.appspot.com/23477042

git-svn-id: svn://svn.chromium.org/blink/trunk@157381 bbb929c8-8fbe-4397-9dbb-9b2b20218538