Mark svg/custom/invisible-text-after-scrolling.xhtml as timing out

This test has been flaky and timing out on XP
so updating TestExpectations.

TBR=haraken
BUG=

Review URL: https://codereview.chromium.org/13931003

git-svn-id: svn://svn.chromium.org/blink/trunk@148413 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Notify embedder of programmatic scrolls

Adds didProgrammaticallyScroll callback to the ChromeClient.
FrameView will notify ChromeClient whenever FrameView::setScrollPosition()
has been called. Only programmatic scrolls use setScrollPosition().

ChromeClient reports programmatic scrolls on the main frame
to WebViewImpl and ultimately forwarded to WebWidgetClient.

R=jamesr@chromium.org
BUG=165317
TEST=webkit_unit_tests:ProgrammaticScrollTest.*

Review URL: https://codereview.chromium.org/14114007

git-svn-id: svn://svn.chromium.org/blink/trunk@148414 bbb929c8-8fbe-4397-9dbb-9b2b20218538