Remove hitTestOverflowControls and some empty functions

BUG=260899

Review URL: https://codereview.chromium.org/49603002

git-svn-id: svn://svn.chromium.org/blink/trunk@160884 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Fixed-position compositing code needs to compute layer bounds as if the layer is composited

When trying to determine whether a fixed-position element is offscreen,
we need to actually compute the layer bounds as if the layer would be
composited.

Before this patch, the layer bounds were being computed with whatever
the layer's current compositing state was, which caused fixed-position
layer with a transform to flip compositing state on every compositing
update.

BUG=293926

Review URL: https://codereview.chromium.org/50363003

git-svn-id: svn://svn.chromium.org/blink/trunk@160885 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Tests for shape-outside with negative margins

New tests for a float with shape-outside when the float has negative
margins. This also updates the positive margin tests to have better
explanations of what each test is testing, and fixes the spec link to be
correct in those tests.

BUG=260357

Review URL: https://codereview.chromium.org/47213004

git-svn-id: svn://svn.chromium.org/blink/trunk@160886 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Remove Internals.attached and related test

This test and the method doesn't make any sense since any node in the main
document is attached (except in really special cases in mutation events).
If this test was trying to cover that ShadowRoots are correctly rendered
we have tons of tests for that now too, so this test is not needed or this
suspect attached() check.

Review URL: https://codereview.chromium.org/50263006

git-svn-id: svn://svn.chromium.org/blink/trunk@160887 bbb929c8-8fbe-4397-9dbb-9b2b20218538