make an image from a mutable bitmap

src/image/SkImagePriv.h

 /*
  * Copyright 2012 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef SkImagePriv_DEFINED
 #define SkImagePriv_DEFINED
 
@@ skipping 18 matching lines @@
  *  they exist on the pixelref.
  *
  *  It is illegal to call this with a texture-backed bitmap.
  *
  *  If the bitmap's colortype cannot be converted into a corresponding
  *  SkImageInfo, or the bitmap's pixels cannot be accessed, this will return
  *  nullptr.
  */
 enum ForceCopyMode {
     kNo_ForceCopyMode,
-    kYes_ForceCopyMode, // must copy the pixels even if the bitmap is immutable
+    kYes_ForceCopyMode,     // must copy the pixels even if the bitmap is immutable
+    kNever_ForceCopyMode,   // don't ever copy, even if the bitmap is mutable
 };
 extern sk_sp<SkImage> SkMakeImageFromRasterBitmap(const SkBitmap&,
                                                   ForceCopyMode = kNo_ForceCopyMode);
 
 // Given an image created from SkNewImageFromBitmap, return its pixelref. This
 // may be called to see if the surface and the image share the same pixelref,
 // in which case the surface may need to perform a copy-on-write.
 extern const SkPixelRef* SkBitmapImageGetPixelRef(const SkImage* rasterImage);
 
 // When a texture is shared by a surface and an image its budgeted status is that of the
 // surface. This function is used when the surface makes a new texture for itself in order
 // for the orphaned image to determine whether the original texture counts against the
 // budget or not.
 extern void SkTextureImageApplyBudgetedDecision(SkImage* textureImage);
 
 // Update the texture wrapped by an image created with NewTexture. This
 // is called when a surface and image share the same GrTexture and the
 // surface needs to perform a copy-on-write
 extern void SkTextureImageSetTexture(SkImage* image, GrTexture* texture);
 
 GrTexture* GrDeepCopyTexture(GrTexture* src, SkBudgeted);
 
 #endif