[WebSocket] Create an isolated copy of the KURL parameter in Bridge::Connect()

WorkerThreadableWebSocketChannel::Bridge::connect() creates a closure of
Peer::connect call from url. Since this closure will be used by the main
thread while this method is called from the worker thread, we need to
create an isolated copy of it.

Recent refactoring changed this method to use CallClosureTask::create +
bind from createCallbackTask. Since createCallbackTask wraps arguments
with CrossThreadCopier, not calling copy() on url was not a problem in
the old code.

On the other hand, in Bridge::initializ(), isolateCopy() call on
sourceURL is redundant since createCallbackTask is used there. This
change removes it.

BUG=351292

Review URL: https://codereview.chromium.org/196023005

git-svn-id: svn://svn.chromium.org/blink/trunk@168992 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Revert XMLHttpRequest's receive-as-blob implementation back to use memory until Chromium is fixed

The RedirectToFile functionality of Chromium on which the current
optimized [1] receive-as-blob code of XHR depends is broken.
Because of the bug, XHR::didDownloadData() handler may be invoked after
XHR::didFinishLoading(). See [2] for detail. As it seems the fix is not
ready for landing but the impact of the bug is big, I'd like to first
revert the optimization in Blink until Chromium is fixed well.

[1] http://src.chromium.org/viewvc/blink?view=revision&revision=163141
[2] https://codereview.chromium.org/82273002/

BUG=347663

Review URL: https://codereview.chromium.org/190583004

git-svn-id: svn://svn.chromium.org/blink/trunk@168993 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Avoid unneeded argument copying in GenericHashTraits

Avoid unneeded argument copying in GenericHashTraits 'peek' and 'passOut'
methods.
The problem was that those methods accepted arguments by const reference
but returned them by value creating extra temporary copies.
This patch makes these methods return the arguments by const reference too
(no temporaries are created), a little decrease of content_shell binary
size is observed: 90110792 - 90106416 = 4376 bytes (Linux x64, GCC 4.6.3,
release static library  build).

Review URL: https://codereview.chromium.org/189513014

git-svn-id: svn://svn.chromium.org/blink/trunk@168994 bbb929c8-8fbe-4397-9dbb-9b2b20218538