Remove FrameView::requestScrollPositionUpdate

It doesn't seem to do anything besides always return false.

Review URL: https://codereview.chromium.org/26303007

git-svn-id: svn://svn.chromium.org/blink/trunk@159959 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Auto-rebaseline for r159729

http://src.chromium.org/viewvc/blink?view=revision&revision=159729

BUG=307324
TBR=eae@chromium.org

Review URL: https://codereview.chromium.org/29173008

git-svn-id: svn://svn.chromium.org/blink/trunk@159960 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Defer the real work in updateCompositingLayers until it's really needed.

Many types of change on a web page end up requiring that
compositing state gets updated. Currently this work is performed
immediately after layout, recalcStyle, and other entry points.

However, this work may happen surprisingly many times per actual
rendered frame, which is absolutely wasteful - nothing except the
most recent compositing state will matter when the frame finally
gets drawn. So, instead we can defer all compositing update work
until the compositor is ready to ask for updated compositing state.

BUG=229679,302726
R=jamesr@chromium.org, vollick@chromium.org

Review URL: https://codereview.chromium.org/26110004

git-svn-id: svn://svn.chromium.org/blink/trunk@159961 bbb929c8-8fbe-4397-9dbb-9b2b20218538