Refactor WritableBuffer interface for more useful ptr management.

media/base/data_buffer.h

Index: media/base/data_buffer.h
===================================================================
--- media/base/data_buffer.h	(revision 20532)
+++ media/base/data_buffer.h	(working copy)
@@ -5,32 +5,40 @@
 // A simple implementation of WritableBuffer that takes ownership of
 // the given data pointer.
 //
-// DataBuffer assumes that memory was allocated with new char[].
+// DataBuffer assumes that memory was allocated with new uint8[].
 
 #ifndef MEDIA_BASE_DATA_BUFFER_H_
 #define MEDIA_BASE_DATA_BUFFER_H_
 
+#include "base/scoped_ptr.h"
 #include "media/base/buffers.h"
 
 namespace media {
 
 class DataBuffer : public WritableBuffer {
  public:
-  DataBuffer();
+  // Takes ownership of the passed |buffer|, assumes valid data of size
+  // |buffer_size|.
+  DataBuffer(uint8* buffer, size_t buffer_size);
 
+  // Allocates buffer of size |buffer_size|. If |buffer_size| is 0, |data_| is
+  // set to a NULL ptr.
+  explicit DataBuffer(size_t buffer_size);
+
   // Buffer implementation.
   virtual const uint8* GetData() const;
   virtual size_t GetDataSize() const;
 
   // WritableBuffer implementation.
-  virtual uint8* GetWritableData(size_t buffer_size);
+  virtual uint8* GetWritableData();
   virtual void SetDataSize(size_t data_size);
+  virtual size_t GetBufferSize() const;
 
  protected:
   virtual ~DataBuffer();
 
  private:
-  uint8* data_;
+  scoped_array<uint8> data_;
   size_t buffer_size_;
   size_t data_size_;
 };