Revert[4] of add ImageShader, sharing code with its Bitmap cousin

src/gpu/SkGrPriv.h

Index: src/gpu/SkGrPriv.h
diff --git a/src/gpu/SkGrPriv.h b/src/gpu/SkGrPriv.h
index 1564d31bc936c1b39447a8cd4e7cf9dd7f366cfd..25fda57d9ec8668ec8781fcbf1b5e5e0e2bb3528 100644
--- a/src/gpu/SkGrPriv.h
+++ b/src/gpu/SkGrPriv.h
@@ -9,6 +9,7 @@
 #define SkGrPriv_DEFINED
 
 #include "GrTypes.h"
+#include "GrTextureAccess.h"
 #include "SkImageInfo.h"
 #include "SkXfermode.h"
 
@@ -31,6 +32,8 @@ struct SkGrStretch {
     int fHeight;
 };
 
+GrTextureParams GrImageUsageToTextureParams(SkImageUsageType);
+
 /**
  *  Our key includes the offset, width, and height so that bitmaps created by extractSubset()
  *  are unique.
@@ -45,6 +48,11 @@ struct SkGrStretch {
 void GrMakeKeyFromImageID(GrUniqueKey* key, uint32_t imageID, const SkIRect& imageBounds,
                           const GrCaps&, SkImageUsageType);
 
+/**
+ *  Given an "unstretched" key, and a stretch rec, produce a stretched key.

[robertphillips, 2015/09/30 19:25:56]

Returns false if the stretched key cannot be created (e.g., the "unstretched"
key wasn't valid).

?

+ */
+bool GrMakeStretchedKey(const GrUniqueKey& origKey, const SkGrStretch&, GrUniqueKey* stretchedKey);
+
 /** Converts an SkPaint to a GrPaint for a given GrContext. The matrix is required in order
     to convert the SkShader (if any) on the SkPaint. */
 bool SkPaintToGrPaint(GrContext*,
@@ -76,4 +84,6 @@ bool SkPaintToGrPaintWithXfermode(GrContext* context,
                                   bool primitiveIsSrc,
                                   GrPaint* grPaint);
 
+bool GrTextureUsageSupported(const GrCaps&, int width, int height, SkImageUsageType);
+
 #endif