Fix crash by focusing multiple-fields input types during a unload event.

ContainerNode::removeChildren:
We should remove focus after dispatching unload events. Document::
m_focusedNode could have an element not in the document tree.

Document::implicitOpen:
Confirm that removeChildren clears m_focusedNode.

BaseMultipleFieldsDateAndTimeInputType::didBlurFromControl:
Protect element() because it might loose the last reference by
setFocus(false).

BUG=249640

Review URL: https://chromiumcodereview.appspot.com/17577013

git-svn-id: svn://svn.chromium.org/blink/trunk@152990 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Fix possible crash in RadioInputType::handleKeydownEvent.

We should protect inputElement against deletion by event handlers.

BUG=252712
TEST=none; This is not testable by a layout test

Review URL: https://chromiumcodereview.appspot.com/17568007

git-svn-id: svn://svn.chromium.org/blink/trunk@152991 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Remove V8Collection.{h,cpp}

- Removed unused methods.
- Moved nodeCollectionIndexedPropertyEnumerator to V8Binding.h and renamed
it to indexedPropertyEnumerator. This method will be embedded into the
generated code in the next CL.

R=abarth

Review URL: https://chromiumcodereview.appspot.com/17615006

git-svn-id: svn://svn.chromium.org/blink/trunk@152992 bbb929c8-8fbe-4397-9dbb-9b2b20218538