[chromium] Remove the background filter blur layout tests
https://bugs.webkit.org/show_bug.cgi?id=112372

Reviewed by James Robinson.

Source/WebCore:

Remove the now-unused hacks to regression test the background
filter blur compositor feature.

* testing/Internals.cpp:
* testing/Internals.h:
(Internals):
* testing/Internals.idl:

LayoutTests:

Given that we now have the ability to write pixel tests directly against
the compositor, these tests are no longer needed to guard against
regressions, and have been duplicated for the compositor as pixel tests
in https://codereview.chromium.org/12518026/ and
https://codereview.chromium.org/12518026/.

* platform/chromium/compositing/filters/background-filter-blur-expected.png: Removed.
* platform/chromium/compositing/filters/background-filter-blur-expected.txt: Removed.
* platform/chromium/compositing/filters/background-filter-blur-off-axis-expected.png: Removed.
* platform/chromium/compositing/filters/background-filter-blur-off-axis-expected.txt: Removed.
* platform/chromium/compositing/filters/background-filter-blur-off-axis.html: Removed.
* platform/chromium/compositing/filters/background-filter-blur-outsets-expected.png: Removed.
* platform/chromium/compositing/filters/background-filter-blur-outsets-expected.txt: Removed.
* platform/chromium/compositing/filters/background-filter-blur-outsets.html: Removed.
* platform/chromium/compositing/filters/background-filter-blur.html: Removed.


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@145970 268f45cc-cd09-0410-ab3c-d52691b4dbfc