remove bitmaps entirely from sprite blits (as source)

BUG=skia:
TBR=

Review URL: https://codereview.chromium.org/1156713004
diff --git a/src/core/SkSpriteBlitter.h b/src/core/SkSpriteBlitter.h
index 0bbc856..5cc483f 100644
--- a/src/core/SkSpriteBlitter.h
+++ b/src/core/SkSpriteBlitter.h
@@ -1,4 +1,3 @@
-
 /*
  * Copyright 2006 The Android Open Source Project
  *
@@ -6,7 +5,6 @@
  * found in the LICENSE file.
  */
 
-
 #ifndef SkSpriteBlitter_DEFINED
 #define SkSpriteBlitter_DEFINED
 
@@ -20,31 +18,25 @@
 
 class SkSpriteBlitter : public SkBlitter {
 public:
-    SkSpriteBlitter(const SkBitmap& source);
+    SkSpriteBlitter(const SkPixmap& source);
 
-    virtual bool setup(const SkBitmap& device, int left, int top, const SkPaint& paint);
+    virtual void setup(const SkBitmap& device, int left, int top, const SkPaint&);
 
-    // overrides
 #ifdef SK_DEBUG
-    virtual void    blitH(int x, int y, int width);
-    virtual void    blitAntiH(int x, int y, const SkAlpha antialias[], const int16_t runs[]);
-    virtual void    blitV(int x, int y, int height, SkAlpha alpha);
-    virtual void    blitMask(const SkMask&, const SkIRect& clip);
+    void blitH(int x, int y, int width) override;
+    void blitAntiH(int x, int y, const SkAlpha antialias[], const int16_t runs[]) override;
+    void blitV(int x, int y, int height, SkAlpha alpha) override;
+    void blitMask(const SkMask&, const SkIRect& clip) override;
 #endif
 
-    static SkSpriteBlitter* ChooseD16(const SkBitmap& source, const SkPaint&,
-                                      SkTBlitterAllocator*);
-    static SkSpriteBlitter* ChooseD32(const SkBitmap& source, const SkPaint&,
-                                      SkTBlitterAllocator*);
+    static SkSpriteBlitter* ChooseD16(const SkPixmap& source, const SkPaint&, SkTBlitterAllocator*);
+    static SkSpriteBlitter* ChooseD32(const SkPixmap& source, const SkPaint&, SkTBlitterAllocator*);
 
 protected:
     const SkBitmap* fDevice;
-    const SkPixmap* fSource;
+    const SkPixmap  fSource;
     int             fLeft, fTop;
     const SkPaint*  fPaint;
-
-private:
-    SkAutoPixmapUnlock fUnlocker;
 };
 
 #endif