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

src/image/SkImage_Base.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_Base_DEFINED
 #define SkImage_Base_DEFINED
 
 #include "SkImage.h"
 #include "SkSurface.h"
 
+enum {
+    kNeedNewImageUniqueID = 0
+};
+
 static SkSurfaceProps copy_or_safe_defaults(const SkSurfaceProps* props) {
     return props ? *props : SkSurfaceProps(0, kUnknown_SkPixelGeometry);
 }
 
 class SkImage_Base : public SkImage {
 public:
-    SkImage_Base(int width, int height, const SkSurfaceProps* props)
-        : INHERITED(width, height)
+    SkImage_Base(int width, int height, uint32_t uniqueID, const SkSurfaceProps* props)
+        : INHERITED(width, height, uniqueID)
         , fProps(copy_or_safe_defaults(props))
     {}
 
     /**
      *  If the props weren't know at constructor time, call this but only before the image is
      *  ever released into the wild (since the props field must appear to be immutable).
      */
     void initWithProps(const SkSurfaceProps& props) {
         SkASSERT(this->unique());   // only viewed by one thread
         SkSurfaceProps* mutableProps = const_cast<SkSurfaceProps*>(&fProps);
@@ skipping 39 matching lines @@
 
 static inline SkImage_Base* as_IB(SkImage* image) {
     return static_cast<SkImage_Base*>(image);
 }
 
 static inline const SkImage_Base* as_IB(const SkImage* image) {
     return static_cast<const SkImage_Base*>(image);
 }
 
 #endif