Instrument performPostLayoutTasks and updateCompositingLayers*

This patch adds instrumentation for tracing the following functions:
1) FrameView::updateCompositingLayersAfterStyleChange
2) FrameView::updateCompositingLayersAfterLayout
3) FrameView::performPostLayoutTasks

BUG=

Review URL: https://chromiumcodereview.appspot.com/22880008

git-svn-id: svn://svn.chromium.org/blink/trunk@156192 bbb929c8-8fbe-4397-9dbb-9b2b20218538