Cleanup: remove ScopedStyleResolver::scopingNode(), use TreeScope instead

No functional change.

BUG=none
TEST=pass layout tests.

Review URL: https://codereview.chromium.org/448073002

git-svn-id: svn://svn.chromium.org/blink/trunk@179778 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Only reattach whitespace siblings when going from no renderer to having one.

We only need to reattach whitespace siblings when we go from having no
renderer to having one. This avoids an n^2 traversal of siblings when
attaching lots of display: none or whitespace (without a renderer) siblings.

This brings us inline with Safari for the whitespace benchmark in the bug,
except for the Shadow DOM overhead that we have due to both Safari and Chrome
having an n^2 in Text::textRendererIsNeeded due to calling
NodeRenderingTraversal::previousSiblingRenderer. If we fix that then we can
run the benchmark in 4ms.

BUG=399816

Review URL: https://codereview.chromium.org/451893002

git-svn-id: svn://svn.chromium.org/blink/trunk@179780 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Remove support for control tints.

This also allows us to remove the paintingDisabled() concept on GraphicsContext, since control tint update was implemented by "painting"
without a canvas, which means walking the render tree to invalidate paint
for controls affected by tint.

BUG=344109

Review URL: https://codereview.chromium.org/444233003

git-svn-id: svn://svn.chromium.org/blink/trunk@179781 bbb929c8-8fbe-4397-9dbb-9b2b20218538