Remove WebLayer::maxScrollPosition().

This code is only used in a test, and cc-side support is going away, so
remove it in Blink.

Review URL: https://codereview.chromium.org/215033003

git-svn-id: svn://svn.chromium.org/blink/trunk@170480 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Mark virtual/gpu/fast/canvas/webgl/webgl-large-texture.html as slow

TBR=kbr@chromium.org
BUG=358313

Review URL: https://codereview.chromium.org/218623010

git-svn-id: svn://svn.chromium.org/blink/trunk@170481 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Turn styleWillChange |newStyle| into a reference

The parameter was never NULL but the code wasn't clear about it.
This lead to a couple of unneeded NULL-checks that obfuscated
what could happen.

Review URL: https://codereview.chromium.org/217563003

git-svn-id: svn://svn.chromium.org/blink/trunk@170482 bbb929c8-8fbe-4397-9dbb-9b2b20218538