Changing imageFilter GM tests to use drawBitmap instead of drawSprite

The motivation is be able to test the filters with scaled SkPicture playback in isolation from the issues that surround usage of drawSprite
Review URL: https://codereview.appspot.com/7060071

git-svn-id: http://skia.googlecode.com/svn/trunk@7152 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/gm/gmmain.cpp b/gm/gmmain.cpp
index 1756389..964bafa 100644
--- a/gm/gmmain.cpp
+++ b/gm/gmmain.cpp
@@ -1402,6 +1402,8 @@
         if (!(gmFlags & GM::kSkipPicture_Flag) && doTileGrid) {
             for(int scaleIndex = 0; scaleIndex < tileGridReplayScales.count(); ++scaleIndex) {
                 SkScalar replayScale = tileGridReplayScales[scaleIndex];
+                if ((gmFlags & GM::kSkipScaledReplay_Flag) && replayScale != 1)
+                    continue;
                 // We record with the reciprocal scale to obtain a replay
                 // result that can be validated against comparisonBitmap.
                 SkScalar recordScale = SkScalarInvert(replayScale);