Simplify WorkerGlobalScopeProxy code

This CL stops using weird static method (WebCore::WorkerGlobalScopeProxy::setCreateDelegate) and introduces WebCore::WorkerGlobalScopeProxyProvider.

- blink::WebViewImpl creates blink::WorkerGlobalScopeProxyProviderImpl and pass the pointer of it to WebCore::Page.
- WebCore::Worker gets the WorkerGlobalScopeProxyProviderImpl from the page of the document and creates WorkerGlobalScopeProxy.

BUG=none

Review URL: https://codereview.chromium.org/80193002

git-svn-id: svn://svn.chromium.org/blink/trunk@162522 bbb929c8-8fbe-4397-9dbb-9b2b20218538
[WebSocket] Print error on JS console when connection is closed before receiving handshake response

BUG=none

Review URL: https://codereview.chromium.org/51763004

git-svn-id: svn://svn.chromium.org/blink/trunk@162523 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Align RenderObject's containingBlock / container

The 2 functions work similarly but they had a lot of tiny
differences for no good reason. This change makes them closer
in intended behavior and adds more code sharing.

While touching the code, I removed some very old comment that
didn't match the current code.

Review URL: https://codereview.chromium.org/64913004

git-svn-id: svn://svn.chromium.org/blink/trunk@162524 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Remove ::part.

Since ::part was deprecated, we should remove ::part from Blink.

BUG=321953

Review URL: https://codereview.chromium.org/82863002

git-svn-id: svn://svn.chromium.org/blink/trunk@162525 bbb929c8-8fbe-4397-9dbb-9b2b20218538