unify pixelref and image ID space, so we can share IDs when we share pixels

include/core/SkImage.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 SkImage_DEFINED
 #define SkImage_DEFINED
 
@@ skipping 265 matching lines @@
      *  a raster-backed bitmap (texture-backed bitmaps are DEPRECATED, and not supported here).
      *
      *  If the mode is kRO (read-only), the resulting bitmap will be marked as immutable.
      *
      *  On succcess, returns true. On failure, returns false and the bitmap parameter will be reset
      *  to empty.
      */
     bool asLegacyBitmap(SkBitmap*, LegacyBitmapMode) const;
     
 protected:
-    SkImage(int width, int height) :
+    SkImage(int width, int height, uint32_t uniqueID) :
         fWidth(width),
         fHeight(height),
-        fUniqueID(NextUniqueID()) {
+        fUniqueID(uniqueID ? uniqueID : NextUniqueID()) {

[f(malita), 2015/07/30 20:24:26]

Nit: since we're using a constant in subclases (kNeedNewImageUniqueID), it seems
a bit odd to compare directly with 0 here.  Can you push the test down into
SkImage_Base() where the constant is visible?

[reed1, 2015/07/30 21:17:08]

Problem: that symbol is in a private header
Solution: move the constructor into .cpp

 
         SkASSERT(width > 0);
         SkASSERT(height > 0);
     }
 
 private:
     const int       fWidth;
     const int       fHeight;
     const uint32_t  fUniqueID;
 
     static uint32_t NextUniqueID();
 
     typedef SkRefCnt INHERITED;
 };
 
 #endif