Timeline: do not rebuild presentation model when category filter changes

Since r168396, we were resetting and rebuilding TimelinePresentationModel
upon category filter change, which effectively lead to unability to see
any records under top-level records with hidden categories, since we were
resetting their expansion state to collapsed and filtering them out along
with all their children.

Drive-by: fix the bug with dispatching RecordAdded events from
TracingTimelineModel -- this should be done when removing complete event
from stack, not when we just added a fresh one.

BUG=
R=yurys@chromium.org

Review URL: https://codereview.chromium.org/349673002

git-svn-id: svn://svn.chromium.org/blink/trunk@176837 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Battery Status API: fix flaky layout tests.

Some refactoring of the battery status layout tests to get
rid of flakyness. TestRunner::didChangeBatteryStatus is
synchronous now (see https://codereview.chromium.org/342343004/),
and the tests have been modified accordingly. The tests have
also been simplified somewhat by removing cleanupAndFinish()
functions with the setPageVisibility("hidden") calls. The latter
appeared unnecessary, as the battery managers are stopped
automatically between the tests. Before each test gc() is
performed to  make sure no unused battery managers are present.

Also remove battery-status tests from TestExpectations.

BUG=384396

Review URL: https://codereview.chromium.org/348343003

git-svn-id: svn://svn.chromium.org/blink/trunk@176838 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Add image-rendering: pixelated.

This adds a new value "pixelated" to the "image-rendering"
property. This value sets the interpolation used when
scaling images to InterpolationNone.

Intent to implement:
https://groups.google.com/a/chromium.org/forum/#!topic/blink-dev/Q8N6FoeoPXI

BUG=260739,106662

Review URL: https://codereview.chromium.org/336693005

git-svn-id: svn://svn.chromium.org/blink/trunk@176839 bbb929c8-8fbe-4397-9dbb-9b2b20218538