[S.P.] Invalidate the document element for view background when needed

LayoutTests/fast/repaint/resources/window-resize-repaint.js

Index: LayoutTests/fast/repaint/resources/window-resize-repaint.js
diff --git a/LayoutTests/fast/repaint/resources/window-resize-repaint.js b/LayoutTests/fast/repaint/resources/window-resize-repaint.js
index b075cfda773618d0304d0c2cc0b669c4403199ed..859b79710d6ec4acee134e250cd2b2b454274c01 100644
--- a/LayoutTests/fast/repaint/resources/window-resize-repaint.js
+++ b/LayoutTests/fast/repaint/resources/window-resize-repaint.js
@@ -31,7 +31,7 @@ if (window.testRunner) {
             internals.startTrackingRepaints(document);
             repaintTest();
             document.body.offsetTop;
-            repaintRects += internals.layerTreeAsText(document, window.internals.LAYER_TREE_INCLUDES_REPAINT_RECTS);
+            repaintRects += internals.layerTreeAsText(document, window.internals.LAYER_TREE_INCLUDES_REPAINT_RECTS | window.internals.LAYER_TREE_INCLUDES_PAINT_INVALIDATION_OBJECTS);

[chrishtr, 2015/03/18 19:30:05]

But it doesn't affect any tests?

[Xianzhu, 2015/03/18 19:36:28]

Yes. I'm running trybots to show the expectation changes in the results, and add
NeedsRebaseline in the next patch set.

             internals.stopTrackingRepaints(document);
         }
         testRunner.setCustomTextOutput(repaintRects);