stop using bitmap-filter flags outside of paint itself, as a step towards really changing them into an enum

BUG=

Review URL: https://codereview.chromium.org/19825002

git-svn-id: http://skia.googlecode.com/svn/trunk@10240 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/gm/downsamplebitmap.cpp b/gm/downsamplebitmap.cpp
index e34effa..5cb971d 100644
--- a/gm/downsamplebitmap.cpp
+++ b/gm/downsamplebitmap.cpp
@@ -64,8 +64,7 @@
             matrix.setScale( curScale, curScale );
 
             SkPaint paint;
-            paint.setFilterBitmap(true);
-            paint.setFlags( paint.getFlags() | SkPaint::kHighQualityFilterBitmap_Flag );
+            paint.setFilterLevel(SkPaint::kHigh_FilterLevel);
 
             canvas->save();
             canvas->translate( (SkScalar) curX, 0.f );