Add size_t bytesWritten() const to SkWStream.

include/core/SkStream.h

Index: include/core/SkStream.h
diff --git a/include/core/SkStream.h b/include/core/SkStream.h
index 29aac1356cbb9ec1c6951e6c53d443b3cedd1c5c..516b036a55e67162227374bf94350eb028ad7327 100644
--- a/include/core/SkStream.h
+++ b/include/core/SkStream.h
@@ -189,6 +189,8 @@ public:
     virtual void newline();
     virtual void flush();
 
+    virtual size_t bytesWritten() const = 0;
+
     // helpers
 
     bool    write8(U8CPU);
@@ -369,9 +371,9 @@ public:
     */
     bool isValid() const { return fFILE != NULL; }
 
-    size_t bytesWritten() const;
     virtual bool write(const void* buffer, size_t size) SK_OVERRIDE;
     virtual void flush() SK_OVERRIDE;
+    virtual size_t bytesWritten() const SK_OVERRIDE;
 
 private:
     SkFILE* fFILE;
@@ -385,7 +387,7 @@ public:
 
     SkMemoryWStream(void* buffer, size_t size);
     virtual bool write(const void* buffer, size_t size) SK_OVERRIDE;
-    size_t bytesWritten() const { return fBytesWritten; }
+    virtual size_t bytesWritten() const SK_OVERRIDE { return fBytesWritten; }
 
 private:
     char*   fBuffer;
@@ -403,12 +405,12 @@ public:
     virtual ~SkDynamicMemoryWStream();
 
     virtual bool write(const void* buffer, size_t size) SK_OVERRIDE;
+    virtual size_t bytesWritten() const SK_OVERRIDE { return fBytesWritten; }
     // random access write
     // modifies stream and returns true if offset + size is less than or equal to getOffset()
     bool write(const void* buffer, size_t offset, size_t size);
     bool read(void* buffer, size_t offset, size_t size);
     size_t getOffset() const { return fBytesWritten; }
-    size_t bytesWritten() const { return fBytesWritten; }
 
     // copy what has been written to the stream into dst
     void copyTo(void* dst) const;
@@ -444,13 +446,16 @@ private:
 
 class SK_API SkDebugWStream : public SkWStream {
 public:
+    SkDebugWStream() : fBytesWritten(0) {}
     SK_DECLARE_INST_COUNT(SkDebugWStream)
 
     // overrides
     virtual bool write(const void* buffer, size_t size) SK_OVERRIDE;
     virtual void newline() SK_OVERRIDE;
+    virtual size_t bytesWritten() const SK_OVERRIDE { return fBytesWritten; }
 
 private:
+    size_t fBytesWritten;
     typedef SkWStream INHERITED;
 };