Remove [NoHeader] interface extended attribute

Perl cruft: Python compiler assumes a header file exists.
This removes a special case and simplifies CG logic by having stub header
files if needed.

R=haraken
BUG=341748

Review URL: https://codereview.chromium.org/208393014

git-svn-id: svn://svn.chromium.org/blink/trunk@169906 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Remove histogram from GraphicsLayerUpdater::rebuildTree

This CL removes a histgram from GraphicsLayerUpdater::rebuildTree. This
histogram accounts for 9.2% of the time spent in
GraphicsLayerUpdater::rebuildTree and 1.6% of the total compositing update in
Polymer's calculator.

R=ojan@chromium.org

Review URL: https://codereview.chromium.org/210093005

git-svn-id: svn://svn.chromium.org/blink/trunk@169908 bbb929c8-8fbe-4397-9dbb-9b2b20218538