First version of bitmap use tracking in SkPictureRecord

src/core/SkPictureRecord.h

Index: src/core/SkPictureRecord.h
===================================================================
--- src/core/SkPictureRecord.h	(revision 13686)
+++ src/core/SkPictureRecord.h	(working copy)
@@ -19,8 +19,9 @@
 #include "SkTemplates.h"
 #include "SkWriter32.h"
 
+class SkBBoxHierarchy;
+class SkOffsetTable;
 class SkPictureStateTree;
-class SkBBoxHierarchy;
 
 // These macros help with packing and unpacking a single byte value and
 // a 3 byte value into/out of a uint32_t
@@ -164,7 +165,9 @@
         fWriter.writeScalar(scalar);
     }
 
-    void addBitmap(const SkBitmap& bitmap);
+    // The command at 'offset' in the skp uses the specified bitmap
+    void trackBitmapUse(int bitmapID, size_t offset);
+    int addBitmap(const SkBitmap& bitmap);
     void addMatrix(const SkMatrix& matrix);
     const SkFlatData* addPaint(const SkPaint& paint) { return this->addPaintPtr(&paint); }
     const SkFlatData* addPaintPtr(const SkPaint* paint);
@@ -294,6 +297,8 @@
     bool     fOptsEnabled;
     int      fInitialSaveCount;
 
+    SkAutoTUnref<SkOffsetTable> fBitmapUseOffsets;
+
     friend class SkPicturePlayback;
     friend class SkPictureTester; // for unit testing