Expand GatherPixelRefs unit test

src/utils/SkPictureUtils.cpp

Index: src/utils/SkPictureUtils.cpp
===================================================================
--- src/utils/SkPictureUtils.cpp	(revision 12922)
+++ src/utils/SkPictureUtils.cpp	(working copy)
@@ -112,14 +112,20 @@
         this->addBitmapFromPaint(paint);
     }
     virtual void drawBitmap(const SkDraw&, const SkBitmap& bitmap,
-                            const SkMatrix&, const SkPaint&) SK_OVERRIDE {
+                            const SkMatrix&, const SkPaint& paint) SK_OVERRIDE {
         this->addBitmap(bitmap);
+        if (SkBitmap::kA8_Config == bitmap.config()) {
+            this->addBitmapFromPaint(paint);
+        }
     }
     virtual void drawBitmapRect(const SkDraw&, const SkBitmap& bitmap,
                                 const SkRect* srcOrNull, const SkRect& dst,
-                                const SkPaint&,
+                                const SkPaint& paint,
                                 SkCanvas::DrawBitmapRectFlags flags) SK_OVERRIDE {
         this->addBitmap(bitmap);
+        if (SkBitmap::kA8_Config == bitmap.config()) {
+            this->addBitmapFromPaint(paint);
+        }
     }
     virtual void drawSprite(const SkDraw&, const SkBitmap& bitmap,
                             int x, int y, const SkPaint& paint) SK_OVERRIDE {