Convert CreateCdmBuffer() to use size_t for |capacity|

media/mojo/common/mojo_shared_buffer_video_frame.h

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef MEDIA_MOJO_COMMON_MOJO_SHARED_BUFFER_VIDEO_FRAME_H_
 #define MEDIA_MOJO_COMMON_MOJO_SHARED_BUFFER_VIDEO_FRAME_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
@@ skipping 20 matching lines @@
 
 // A derived class of media::VideoFrame holding a mojo::SharedBufferHandle
 // which is mapped on constructor and remains so for the lifetime of the
 // object. These frames are ref-counted.
 class MojoSharedBufferVideoFrame : public VideoFrame {
  public:
   // Callback called when this object is destructed. Ownership of the shared
   // memory is transferred to the callee.
   using MojoSharedBufferDoneCB =
       base::Callback<void(mojo::ScopedSharedBufferHandle buffer,
-                          uint32_t capacity)>;
+                          size_t capacity)>;
 
   // Creates a new I420 frame in shared memory with provided parameters
   // (coded_size() == natural_size() == visible_rect()), or returns nullptr.
   // Buffers for the frame are allocated but not initialized. The caller must
   // not make assumptions about the actual underlying sizes, but check the
   // returned VideoFrame instead.
   static scoped_refptr<MojoSharedBufferVideoFrame> CreateDefaultI420(
       const gfx::Size& dimensions,
       base::TimeDelta timestamp);
 
@@ skipping 62 matching lines @@
   uint8_t* shared_buffer_data_;
   size_t offsets_[kMaxPlanes];
   MojoSharedBufferDoneCB mojo_shared_buffer_done_cb_;
 
   DISALLOW_COPY_AND_ASSIGN(MojoSharedBufferVideoFrame);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_MOJO_COMMON_MOJO_SHARED_BUFFER_VIDEO_FRAME_H_