ServiceWorkerRegistration::unregister returns false when the registration is already unregistered. (3/3)

1. [Blink] https://codereview.chromium.org/549093002/
2. [Chromium] https://codereview.chromium.org/554573002/
3. [Blink] this patch

BUG=390894
TEST=run_webkit_tests.py http/tests/serviceworker/unregister.html

Review URL: https://codereview.chromium.org/550093002

git-svn-id: svn://svn.chromium.org/blink/trunk@181783 bbb929c8-8fbe-4397-9dbb-9b2b20218538
ServiceWorker: Implement navigator.serviceWorker.getRegistration [1/3]

This is the first step towards implementing getRegistration method of
ServiceWorkerContainer. This patch adds definition of the method and
its callback type to WebServiceWorkerProvider.

[2/3] https://codereview.chromium.org/535753002/
[3/3] https://codereview.chromium.org/540823003/

BUG=404951
TEST=compile (tests will be added by subsequent patches)

Review URL: https://codereview.chromium.org/553983010

git-svn-id: svn://svn.chromium.org/blink/trunk@181784 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Improve <textarea> validation performance.

HTMLTextAreaElement::value() is a costly operation, and we can avoid it
if a <textarea> has neither 'required' attribute nor 'maxlength' attribute.

This CL improves PerformanceTests/DOM/textarea-dom.html and
textarea-edit.html by a few percent.

BUG=

Review URL: https://codereview.chromium.org/543403003

git-svn-id: svn://svn.chromium.org/blink/trunk@181785 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Remove obsolete HitTestResult.targetNode

This has been an alias for innerNode with a "remove this" FIXME for some
time.  The cleanup is pretty easy.

BUG=

Review URL: https://codereview.chromium.org/476303002

git-svn-id: svn://svn.chromium.org/blink/trunk@181786 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Convert RenderFlexibleBox code to use RenderBox references

RenderFlexibleBox has several methods that take pointers to RenderBox instances but
those methods assumes that the objects will never be NULL. We should replace them by
references. This makes the caller code safer.

Review URL: https://codereview.chromium.org/555213002

git-svn-id: svn://svn.chromium.org/blink/trunk@181787 bbb929c8-8fbe-4397-9dbb-9b2b20218538