Move the user agent styles sheets to blink_resources.grd (Part 1) with conditional includes

This is continuation to earlier CL [1] with the conditional statements being added for
specific platform CSS file includes.

Part 1: https://codereview.chromium.org/436843004/
Part 2: https://codereview.chromium.org/422023008/
Part 3: https://codereview.chromium.org/438843004/

BUG=312586
NOTRY=true
TBR=jochen@chromium.org

Review URL: https://codereview.chromium.org/440683004

git-svn-id: svn://svn.chromium.org/blink/trunk@179504 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Fix OutlineValue::visuallyEqual() to check offset

BUG=399798
TEST=fast/repaint/outline-change-offset.html
R=jchaffraix@chromium.org

Review URL: https://codereview.chromium.org/439013002

git-svn-id: svn://svn.chromium.org/blink/trunk@179505 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Move "Heap snapshot statistics" pie chart out of experiment

BUG=None
R=alph@chromium.org

Review URL: https://codereview.chromium.org/445553004

git-svn-id: svn://svn.chromium.org/blink/trunk@179506 bbb929c8-8fbe-4397-9dbb-9b2b20218538