Revert of SkVarAlloc::approxBytesAllocated

src/core/SkVarAlloc.h

Index: src/core/SkVarAlloc.h
diff --git a/src/core/SkVarAlloc.h b/src/core/SkVarAlloc.h
index 9eac6588280213d2d7063da547aecf2fa0b370e6..2b5401b7f06bf81a18f9a58afb0b1684551bd13e 100644
--- a/src/core/SkVarAlloc.h
+++ b/src/core/SkVarAlloc.h
@@ -23,10 +23,6 @@
         return ptr;
     }
 
-    // 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;
-
 private:
     void makeSpace(size_t bytes, unsigned flags);