Fix XMLHttpRequest leak document when send() is called multiple times.

XMLHttpRequest creates a ThreadableLoader which may call XHR async, so it setPendingActivity() to avoid being destroyed. However, before this patch, unsetPendingActivity() was called asynchronously after ThreadableLoader was destroyed, so it lead to multiple problems:
a) When next m_loader was set in send() with pending unsetPendingActivity(), the pendingActivity may be dropped even when there exists new m_loader need protection.
b) pendingActivity may be set multiple times from pending unsetPendingActivity(), but dropProtectionSoon() only decrements m_pendingActivityCount by one, leading to a leak.

This patch fix the above problems by unsetPendingActivity() synchronously with m_loader destruction where possible. XMLHttpRequest::stop() still uses asynchronous unsetPendingActivity() to workaround issues mentioned in r152266.

The file "leak-check.js" was moved from fast/dom to fast/js to enable access from http tests.

BUG=270000

Review URL: https://chromiumcodereview.appspot.com/23005006

git-svn-id: svn://svn.chromium.org/blink/trunk@156078 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Remove Element::uaShadowElementById.

The function has no benefit. userAgentShadowRoot is always non-null
whenever this function is used.

BUG=

Review URL: https://chromiumcodereview.appspot.com/23162003

git-svn-id: svn://svn.chromium.org/blink/trunk@156079 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Remove support for [IsIndex] IDL extended attribute

Remove support for [IsIndex] IDL extended attribute as it is no longer
needed and it increases the complexity of the bindings generator.

BUG=237739

Review URL: https://chromiumcodereview.appspot.com/22962003

git-svn-id: svn://svn.chromium.org/blink/trunk@156080 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Make drag-and-drop autoscroll within frames

This patch makes drag-and-drop autoscroll to all direction in main frame and subframe.

Changes are:
- RenderBox::RenderBox::calculateAutoscrollDirection(): Use proper coordinate of bounding box for RenderView, which is associated to BODY/FRAME element.
- AutoscrollController::updateDragAndDrop(): Don't stop autoscroll timer when updateDragAndDrop() is called for frames other than last drop target frame.

BUG=227728
TEST=fast/events/drag-and-drop-autoscroll-frameset.html, fast/events/drag-and-drop-autoscroll-mainframe.html
R=morrita@chromium.org

Review URL: https://codereview.chromium.org/23175003

git-svn-id: svn://svn.chromium.org/blink/trunk@156081 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Revert 156078 "Fix XMLHttpRequest leak document when send() is c..."

> Fix XMLHttpRequest leak document when send() is called multiple times.
> 
> XMLHttpRequest creates a ThreadableLoader which may call XHR async, so it setPendingActivity() to avoid being destroyed. However, before this patch, unsetPendingActivity() was called asynchronously after ThreadableLoader was destroyed, so it lead to multiple problems:
> a) When next m_loader was set in send() with pending unsetPendingActivity(), the pendingActivity may be dropped even when there exists new m_loader need protection.
> b) pendingActivity may be set multiple times from pending unsetPendingActivity(), but dropProtectionSoon() only decrements m_pendingActivityCount by one, leading to a leak.
> 
> This patch fix the above problems by unsetPendingActivity() synchronously with m_loader destruction where possible. XMLHttpRequest::stop() still uses asynchronous unsetPendingActivity() to workaround issues mentioned in r152266.
> 
> The file "leak-check.js" was moved from fast/dom to fast/js to enable access from http tests.
> 
> BUG=270000
> 
> Review URL: https://chromiumcodereview.appspot.com/23005006

TBR=kouhei@chromium.org

Review URL: https://codereview.chromium.org/23180002

git-svn-id: svn://svn.chromium.org/blink/trunk@156082 bbb929c8-8fbe-4397-9dbb-9b2b20218538