Pepper: Move FileIO host from renderer to browser.

This change is large because it moves QuotaFileIO and PepperFileIOHost all at
once to the browser process. Some code in the refactored PepperFileIOHost is
moved from what's provided in FileAPIMessageFilter.

Tested locally with Bastion, From Dust, and Angry Bots.

TBR=jschuh
BUG=246396

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=232440

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=232547

Review URL: https://codereview.chromium.org/33053002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@234883 0039d316-1c4b-4281-b951-d872f2087c98
Android: keep a "heartbeat" for perf tests.

The script's output is "buffered" so it can be retried on case of failures
without messing up the higher level log parsing.
This however triggers the buildbot watchdog, which kills the tests since
it doesn't produce any output.
Print a hearbeat message to indicate the --single-step step script is
alive and kicking.

BUG=318369
NOTRY=True

Review URL: https://codereview.chromium.org/68503009

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@234884 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 234884