start to remove lockPixels from bitmapshader

src/core/SkBitmapProcState.h

Index: src/core/SkBitmapProcState.h
diff --git a/src/core/SkBitmapProcState.h b/src/core/SkBitmapProcState.h
index 2522a69e7f0e59c776be86663b0f85abcd658f2e..d5a354e36aca7b9a03579ae99b252647ca4cb53a 100644
--- a/src/core/SkBitmapProcState.h
+++ b/src/core/SkBitmapProcState.h
@@ -13,6 +13,7 @@
 #include "SkBitmap.h"
 #include "SkBitmapFilter.h"
 #include "SkMatrix.h"
+#include "SkPaint.h"
 #include "SkScaledImageCache.h"
 
 #define FractionalInt_IS_64BIT
@@ -160,7 +161,13 @@ private:
     bool chooseProcs(const SkMatrix& inv, const SkPaint&);
     ShaderProc32 chooseShaderProc32();
 
-    void possiblyScaleImage();
+    // returns false if we did not try to scale the image. In that case, we
+    // will need to "lock" its pixels some other way.
+    bool possiblyScaleImage();
+
+    // returns false if we failed to "lock" the pixels at all. Typically this
+    // means we have to abort the shader.
+    bool lockBaseBitmap();
 
     SkBitmapFilter* fBitmapFilter;