[S.P.] Don't draw frames of animated images that are offscreen.

LayoutTests/fast/repaint/resources/text-based-repaint.js

 // Asynchronous tests should manually call finishRepaintTest at the appropriate
 // time.
 window.testIsAsync = false;
 window.outputRepaintRects = true;
 window.generateMinimumRepaint = false; // See comments about 'Minimum repaint' below.
 
-function runRepaintTest()
+function runRepaintTest(timeout)
 {
     if (!window.testRunner || !window.internals) {
-        setTimeout(repaintTest, 500);
+        setTimeout(repaintTest, timeout || 500);
         return;
     }
 
     // TODO(enne): this is a workaround for multiple svg onload events.
     // See: http://crbug.com/372946
     if (window.hasRunRepaintTest)
         return;
     window.hasRunRepaintTest = true;
 
     if (window.enablePixelTesting)
@@ skipping 170 matching lines @@
             } else {
                 var newRect = [xBegin, y, xWidth, 1];
                 nextRectsMayContinue.push(newRect);
                 result.push(newRect);
             }
         }
         rectsMayContinue = nextRectsMayContinue;
     }
     return result;
 }