Add an Android-framework-only stable ID to SkPixelRef.

include/core/SkPixelRef.h

Index: include/core/SkPixelRef.h
diff --git a/include/core/SkPixelRef.h b/include/core/SkPixelRef.h
index 6f0421e3c4f36dbf11d440b75225ed65a15a1c04..766fa7ffffd1218a6b2f983e149d6402188546aa 100644
--- a/include/core/SkPixelRef.h
+++ b/include/core/SkPixelRef.h
@@ -127,6 +127,17 @@ public:
     */
     uint32_t getGenerationID() const;
 
+#ifdef SK_BUILD_FOR_ANDROID_FRAMEWORK
+    /** Returns a non-zero, unique value corresponding to this SkPixelRef,
+        which is unchanged when the pixels are changed and even when this
+        object is deleted.
+
+        Can be used as a key which must remain unique across changes and
+        deletions.
+     */
+    uint32_t getStableID() const;
+#endif
+
     /**
      *  Call this if you have changed the contents of the pixels. This will in-
      *  turn cause a different generation ID value to be returned from
@@ -358,6 +369,9 @@ private:
 
     mutable SkTRacy<uint32_t> fGenerationID;
     mutable SkTRacy<bool>     fUniqueGenerationID;
+#ifdef SK_BUILD_FOR_ANDROID_FRAMEWORK
+    mutable SkTRacy<uint32_t> fStableID;

[mtklein, 2014/11/24 19:12:41]

const uint32_t and fill it in the constructor?  It's not going to change...

[scroggo, 2014/11/24 19:20:25]

Done.

+#endif
 
     SkTDArray<GenIDChangeListener*> fGenIDChangeListeners;  // pointers are owned