Don't fire popstate event on initial document load

According to the specification [1], a popstate event should only be fired
when the document has a "last entry" and the entry being navigated to isn't
it.  A document is created without a "last entry" and gets one just after
this check when it is first navigated to, so a popstate should be fired any
time a document is navigated to except for the first time after it has been
created.

[1] http://www.whatwg.org/specs/web-apps/current-work/multipage/history.html#traverse-the-history (step 12-14 in particular)

BUG=63040

Review URL: https://codereview.chromium.org/136463002

git-svn-id: svn://svn.chromium.org/blink/trunk@165221 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Fix LayoutTests/plugins/npruntime/enumerate.html

The test was failing because 'for .. in' implementation requires
properties to be recognizable by 'GetProperty' of the NP runtime
implementation (TestObject).

As the test was terminating prematurely, the second problem had been left
unnoticed: 'Object.keys' was returning '0,0,bar,foo' because VPNPObject
was adding all enumerated properties twice: first as indexes, then as
properties.

Review URL: https://codereview.chromium.org/137283006

git-svn-id: svn://svn.chromium.org/blink/trunk@165222 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Remove fake heap snapshot worker

The fake worker was added when we used DumpRenderTree to run layout tests and DRT didn't support web workers. Now we can use real workers in layout tests and there is no need to keep fake implementation.

BUG=324769
R=alph@chromium.org

Review URL: https://codereview.chromium.org/140873002

git-svn-id: svn://svn.chromium.org/blink/trunk@165223 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Check for duplicate ArrayBuffer transferables.

Attempts to pass duplicate transferable object should be caught by
postMessage(),

  http://www.whatwg.org/specs/web-apps/current-work/#dom-window-postmessage
  http://www.whatwg.org/specs/web-apps/current-work/#dom-messageport-postmessage

Add the required case for ArrayBuffer.

R=mkwst,dslomov
BUG=334397

Review URL: https://codereview.chromium.org/138273013

git-svn-id: svn://svn.chromium.org/blink/trunk@165224 bbb929c8-8fbe-4397-9dbb-9b2b20218538