Merge FrameLoader::loadURL() into FrameLoader::load().

Merge FrameLoader::loadURLIntoChildFrame() into its only callsite in
WebFrameImpl and have it call load() or loadItem() as appropriate.

Break FrameLoader::load() out into some helper functions for readability.

BUG=none

Review URL: https://chromiumcodereview.appspot.com/19108003

git-svn-id: svn://svn.chromium.org/blink/trunk@154507 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Remove unecessary malloc seen in http://sina.com.cn (#17)

Content calls down into Blink a bunch of times during loading to
check the document's encoding.  Every time we were allocating a
new copy of a constant string.  The right fix is to fix TextEncoding
to have fancier static-string technology, but this is the quick-fix
to get this malloc off the profile of http://sina.com.cn.

BUG=261689

Review URL: https://chromiumcodereview.appspot.com/19663003

git-svn-id: svn://svn.chromium.org/blink/trunk@154508 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Mark WebFrameTest.ContextNotificationsLoadUnload as Flaky.

This test fails sometimes, it's been causing false alarms in
garden-o-matic.

TBR=cbiesinger@chromium.org
BUG=261691

Review URL: https://codereview.chromium.org/19771006

git-svn-id: svn://svn.chromium.org/blink/trunk@154509 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Make more members of RuleFeatureSet private

RuleFeatureSet used to be a struct and all of its logic
was spread all over the code, including StyleResolver.

This is just another baby step towards moving all of the logic
related to RuleFeatureSet into one place.

BUG=237268

Review URL: https://chromiumcodereview.appspot.com/19700003

git-svn-id: svn://svn.chromium.org/blink/trunk@154510 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Support 'extend-to-zoom' viewport descriptor value

Based on patch from Kenneth Rohde Christiansen <kenneth.r.christiansen@intel.com>.

See http://dev.w3.org/csswg/css-device-adapt for details.

This new feature is enabled only for UA and user style sheets.

Review URL: https://chromiumcodereview.appspot.com/19632002

git-svn-id: svn://svn.chromium.org/blink/trunk@154511 bbb929c8-8fbe-4397-9dbb-9b2b20218538