O(1) SkPictureUtils::ApproxBytesUsed()

src/core/SkVarAlloc.h

Index: src/core/SkVarAlloc.h
diff --git a/src/core/SkVarAlloc.h b/src/core/SkVarAlloc.h
index 8a55b366155fdfafdd598511a374876ffd565d24..e8236cf9920067864a0261a09a1e70aa3b536dc6 100644
--- a/src/core/SkVarAlloc.h
+++ b/src/core/SkVarAlloc.h
@@ -35,12 +35,14 @@ public:
     }
 
     // Returns our best estimate of the number of bytes we've allocated.
-    // (We intentionally do not track this precisely to save space.)
-    size_t approxBytesAllocated() const;
+    // (We may not track this precisely to save space.)
+    size_t approxBytesAllocated() const { return fBytesAllocated; }
 
 private:
     void makeSpace(size_t bytes, unsigned flags);
 
+    size_t fBytesAllocated;
+
     char* fByte;
     unsigned fRemaining;
     unsigned fLgSize;
@@ -48,6 +50,6 @@ private:
     struct Block;
     Block* fBlock;
 };
-SK_COMPILE_ASSERT(sizeof(SkVarAlloc) <= 24, SkVarAllocSize);
+SK_COMPILE_ASSERT(sizeof(SkVarAlloc) <= 32, SkVarAllocSize);
 
 #endif//SkVarAlloc_DEFINED