Remove GetActiveEntry usage from content.

This is a copy of https://chromiumcodereview.appspot.com/23022006, which was reverted due to perf regression. The root cause was WebContentsImpl::GetWebkitPrefs using GetLastCommittedEntry, which caused compositing to be disabled and higher memory usage on Mac. I've removed that part of the change and will investigate separately how to best fix it.

BUG=273710

Review URL: https://codereview.chromium.org/25654005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@227665 0039d316-1c4b-4281-b951-d872f2087c98
cc: Removed unused metrics from RenderingStats.

- Removed everything except for frame count, paint/record/rasterize time and
pixel count.
- Cleaned up variable naming.
- Removed RasterStats struct. Replaced by direct usage of
RenderingStatsInstrumentation.

R=nduca@chromium.org
BUG=234308,280638

Review URL: https://codereview.chromium.org/26031002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@227666 0039d316-1c4b-4281-b951-d872f2087c98
Pepper: Style nits for QuotaFileIO.

This cleans up some renderer-specific stuff to make it easier to read the code
changes when moving QuotaFileIO to the browser.

BUG=246396

Review URL: https://codereview.chromium.org/26560003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@227667 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 227667