change SkDraw and all Blitters to use pixmap instead of bitmap

src/core/SkAAClip.h

Index: src/core/SkAAClip.h
diff --git a/src/core/SkAAClip.h b/src/core/SkAAClip.h
index 1daeb38f598f328552b033b18567fa1dba055673..9f6a3d6012260d7c1710e6347e5a881430be89fd 100644
--- a/src/core/SkAAClip.h
+++ b/src/core/SkAAClip.h
@@ -110,12 +110,11 @@ public:
     }
 
     void blitH(int x, int y, int width) override;
-    virtual void blitAntiH(int x, int y, const SkAlpha[],
-                           const int16_t runs[]) override;
+    void blitAntiH(int x, int y, const SkAlpha[], const int16_t runs[]) override;
     void blitV(int x, int y, int height, SkAlpha alpha) override;
     void blitRect(int x, int y, int width, int height) override;
     void blitMask(const SkMask&, const SkIRect& clip) override;
-    const SkBitmap* justAnOpaqueColor(uint32_t* value) override;
+    const SkPixmap* justAnOpaqueColor(uint32_t* value) override;
 
 private:
     SkBlitter*      fBlitter;