Replace many [TreatReturnedNullStringAs=Null] with nullable DOMString

In IDL files, the attribute declarations

  [TreatReturnedNullStringAs=Null] readonly attribute DOMString X;
  [TreatReturnedNullStringAs=Null, TreatNullAs=NullString] attribute DOMString X;

can now be changed into

  readonly attribute DOMString? X;
  attribute DOMString? X;

without changing behavior or generated code, so do that.

Similarly for methods, the declaration

  [TreatReturnedNullStringAs=Null] DOMString f();

can be changed into

  DOMString? f();

without changing behavior or generated code, so do that too.

Review URL: https://codereview.chromium.org/361883004

git-svn-id: svn://svn.chromium.org/blink/trunk@177302 bbb929c8-8fbe-4397-9dbb-9b2b20218538
gardening: mark inspector-protocol/css/media-query-listener-exception.html as flaky on win also

BUG=390445
TBR=pilgrim@chromium.org

Review URL: https://codereview.chromium.org/363653004

git-svn-id: svn://svn.chromium.org/blink/trunk@177303 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Oilpan: Clear out memory when the memory is added to a free list

This CL changes a place where memory is cleared out.
Before this CL, memory was cleared out in Heap::allocate().
After this CL, memory is cleared out when added to a free list.

This is good for:

- preventing freed memory from being exploited.
- improving performance of Heap::allocate().

BUG=

Review URL: https://codereview.chromium.org/353343002

git-svn-id: svn://svn.chromium.org/blink/trunk@177304 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Fix performance regression of tiny-innerHTML.html caused by r176901

The reason of the performance regressions was I added the following check to ScriptController::canExecuteScripts()

if (!context.IsEmpty() && toDOMWindow(context) && DOMWrapperWorld::current(m_isolate).isPrivateScriptIsolatedWorld()) {
    return true;
}

This CL moves this check to the last of canExecuteScripts(). In other words, the check runs only when canExecuteScripts() is going to return false. This will fix the performance regression since tiny-innerHTML.html always return true for canExecuteScripts().

BUG=389287

Review URL: https://codereview.chromium.org/367613004

git-svn-id: svn://svn.chromium.org/blink/trunk@177305 bbb929c8-8fbe-4397-9dbb-9b2b20218538