Convert CreateCdmBuffer() to use size_t for |capacity|

media/cdm/cdm_allocator.h

Index: media/cdm/cdm_allocator.h
diff --git a/media/cdm/cdm_allocator.h b/media/cdm/cdm_allocator.h
index f8023a87e031c2b26f37db3bade9df915124b2c2..84e7f3057e24a1b41bc7d5bb0743352b26403370 100644
--- a/media/cdm/cdm_allocator.h
+++ b/media/cdm/cdm_allocator.h
@@ -5,6 +5,7 @@
 #ifndef MEDIA_CDM_CDM_ALLOCATOR_H_
 #define MEDIA_CDM_CDM_ALLOCATOR_H_
 
+#include <stddef.h>
 #include <stdint.h>
 
 #include "base/macros.h"
@@ -25,7 +26,7 @@ class MEDIA_EXPORT CdmAllocator {
 
   // Creates a buffer with at least |capacity| bytes. Caller is required to
   // call Destroy() on the returned buffer when it is done with it.
-  virtual cdm::Buffer* CreateCdmBuffer(uint32_t capacity) = 0;
+  virtual cdm::Buffer* CreateCdmBuffer(size_t capacity) = 0;
 
   // Returns a new VideoFrameImpl.
   virtual scoped_ptr<VideoFrameImpl> CreateCdmVideoFrame() = 0;