Lots of files touched for a very simple change. Everywhere we used a const MediaFormat* we now

use a const MediaFormat&.  This makes for simpler code and for better pointer reference safety.

Review URL: http://codereview.chromium.org/42635

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@12623 0039d316-1c4b-4281-b951-d872f2087c98

30 files changed, 119 insertions, 122 deletions

diff --git a/chrome/renderer/media/audio_renderer_impl.cc b/chrome/renderer/media/audio_renderer_impl.cc
index 5df76ba..9677b32 100644
--- a/chrome/renderer/media/audio_renderer_impl.cc
+++ b/chrome/renderer/media/audio_renderer_impl.cc
@@ -29,14 +29,14 @@ AudioRendererImpl::~AudioRendererImpl() {
 }
 
 bool AudioRendererImpl::IsMediaFormatSupported(
-    const media::MediaFormat* media_format) {
+    const media::MediaFormat& media_format) {
   int channels;
   int sample_rate;
   int sample_bits;
   return ParseMediaFormat(media_format, &channels, &sample_rate, &sample_bits);
 }
 
-bool AudioRendererImpl::OnInitialize(const media::MediaFormat* media_format) {
+bool AudioRendererImpl::OnInitialize(const media::MediaFormat& media_format) {
   // Parse integer values in MediaFormat.
   int channels;
   int sample_rate;
@@ -156,7 +156,3 @@ void AudioRendererImpl::OnNotifyAudioPacketReady() {
     delegate_->view()->NotifyAudioPacketReady(stream_id_, filled);
   }
 }
-
-const media::MediaFormat* AudioRendererImpl::GetMediaFormat() {
-  return &media_format_;
-}
diff --git a/chrome/renderer/media/audio_renderer_impl.h b/chrome/renderer/media/audio_renderer_impl.h
index c0a8257..d062bb0 100644
--- a/chrome/renderer/media/audio_renderer_impl.h
+++ b/chrome/renderer/media/audio_renderer_impl.h
@@ -108,7 +108,7 @@ class AudioRendererImpl : public media::AudioRendererBase {
     return new media::FilterFactoryImpl1<AudioRendererImpl,
                                          WebMediaPlayerDelegateImpl*>(delegate);
   }
-  static bool IsMediaFormatSupported(const media::MediaFormat* format);
+  static bool IsMediaFormatSupported(const media::MediaFormat& format);
 
   // Methods call from RenderView when audio related IPC messages are received
   // from browser process.
@@ -123,7 +123,6 @@ class AudioRendererImpl : public media::AudioRendererBase {
   // Methods called on pipeline thread ----------------------------------------
   // media::MediaFilter implementation.
   virtual void SetPlaybackRate(float rate);
-  const media::MediaFormat* GetMediaFormat();
 
   // media::AudioRenderer implementation.
   virtual void SetVolume(float volume);
@@ -134,7 +133,7 @@ class AudioRendererImpl : public media::AudioRendererBase {
  protected:
   // Methods called on audio renderer thread ----------------------------------
   // These methods are called from AudioRendererBase.
-  virtual bool OnInitialize(const media::MediaFormat* media_format);
+  virtual bool OnInitialize(const media::MediaFormat& media_format);
   virtual void OnStop();
 
  private:
@@ -159,9 +158,6 @@ class AudioRendererImpl : public media::AudioRendererBase {
 
   WebMediaPlayerDelegateImpl* delegate_;
 
-  // A map of media format information.
-  media::MediaFormat media_format_;
-
   // ID of the stream created in the browser process.
   int32 stream_id_;
 
diff --git a/chrome/renderer/media/data_source_impl.cc b/chrome/renderer/media/data_source_impl.cc
index e084413..51efb6f 100644
--- a/chrome/renderer/media/data_source_impl.cc
+++ b/chrome/renderer/media/data_source_impl.cc
@@ -215,10 +215,10 @@ void DataSourceImpl::OnInitialize(std::string uri) {
       "GET",
       GURL(uri),
       GURL(uri),
-      GURL(),        // TODO(hclam): provide referer here.
-      "null",        // TODO(abarth): provide frame_origin
-      "null",        // TODO(abarth): provide main_frame_origin
-      std::string(), // Provide no header.
+      GURL(),         // TODO(hclam): provide referer here.
+      "null",         // TODO(abarth): provide frame_origin
+      "null",         // TODO(abarth): provide main_frame_origin
+      std::string(),  // Provide no header.
       // Prefer to load from cache, also enable downloading the file, the
       // resource will be saved to a single response data file if it's possible.
       net::LOAD_PREFERRING_CACHE | net::LOAD_ENABLE_DOWNLOAD_FILE,
@@ -244,9 +244,9 @@ void DataSourceImpl::OnDownloadProgress(uint64 position, uint64 size) {
     AutoLock auto_lock(lock_);
     downloaded_bytes_ = position;
     if (!total_bytes_known_) {
-      if (size == kuint64max)
+      if (size == kuint64max) {
         total_bytes_ = position;
-      else {
+      } else {
         total_bytes_ = size;
         total_bytes_known_ = true;
       }
@@ -308,6 +308,6 @@ std::string DataSourceImpl::GetURLForDebugging() {
   return uri_;
 }
 
-const media::MediaFormat* DataSourceImpl::GetMediaFormat() {
-  return &media_format_;
+const media::MediaFormat& DataSourceImpl::media_format() {
+  return media_format_;
 }
diff --git a/chrome/renderer/media/data_source_impl.h b/chrome/renderer/media/data_source_impl.h
index 9190b25..6f8d688 100644
--- a/chrome/renderer/media/data_source_impl.h
+++ b/chrome/renderer/media/data_source_impl.h
@@ -136,7 +136,7 @@ class DataSourceImpl : public media::DataSource,
   virtual bool SetPosition(int64 position);
   virtual bool GetSize(int64* size_out);
 
-  const media::MediaFormat* GetMediaFormat();
+  const media::MediaFormat& media_format();
 
  private:
   friend class media::FilterFactoryImpl1<DataSourceImpl,
@@ -164,7 +164,7 @@ class DataSourceImpl : public media::DataSource,
   // in construction and can be accessed in all threads safely.
   WebMediaPlayerDelegateImpl* delegate_;
 
-  // Message loop of render thread.	
+  // Message loop of render thread.
   MessageLoop* render_loop_;
 
   // A common lock for protecting members accessed by multiple threads.
@@ -173,7 +173,7 @@ class DataSourceImpl : public media::DataSource,
   // A flag that indicates whether this object has been called to stop.
   bool stopped_;
 
-  // URI to the resource being downloaded.	
+  // URI to the resource being downloaded.
   std::string uri_;
 
   // Members for keeping track of downloading progress.
diff --git a/media/base/factory.h b/media/base/factory.h
index 66bc377..91e5bc4 100644
--- a/media/base/factory.h
+++ b/media/base/factory.h
@@ -24,7 +24,7 @@
 //
 //   Returns true and assigns |filter_out| if the filter was created, false
 //   and assigns NULL otherwise.
-//   static bool Create(MediaFormat* media_format, YourFilterType** filter_out);
+//   static bool Create(MediaFormat& media_format, YourFilterType** filter_out);
 //
 
 #ifndef MEDIA_BASE_FACTORY_H_
@@ -47,7 +47,7 @@ class FilterFactory : public base::RefCountedThreadSafe<FilterFactory> {
   // If the factory does not support the specific filter type or does not
   // support the |media_format| then NULL is returned.
   template <class Filter>
-  Filter* Create(const MediaFormat* media_format) {
+  Filter* Create(const MediaFormat& media_format) {
     return reinterpret_cast<Filter*>(Create(Filter::filter_type(),
                                             media_format));
   }
@@ -63,7 +63,7 @@ class FilterFactory : public base::RefCountedThreadSafe<FilterFactory> {
   // It is assumed that the MediaFilter interface can be safely cast to the
   // corresponding interface type (i.e., FILTER_AUDIO_DECODER -> AudioDecoder).
   virtual MediaFilter* Create(FilterType filter_type,
-                              const MediaFormat* media_format) = 0;
+                              const MediaFormat& media_format) = 0;
 
   friend class base::RefCountedThreadSafe<FilterFactory>;
   virtual ~FilterFactory() {}
@@ -82,7 +82,7 @@ class FilterFactoryCollection : public FilterFactory {
 
  protected:
   // Attempts to create a filter by walking down the list of filter factories.
-  MediaFilter* Create(FilterType filter_type, const MediaFormat* media_format) {
+  MediaFilter* Create(FilterType filter_type, const MediaFormat& media_format) {
     MediaFilter* filter = NULL;
     for (FactoryVector::iterator factory = factories_.begin();
          !filter && factory != factories_.end();
@@ -113,7 +113,7 @@ class FilterFactoryImpl0 : public FilterFactory {
 
  protected:
   virtual MediaFilter* Create(FilterType filter_type,
-                              const MediaFormat* media_format) {
+                              const MediaFormat& media_format) {
     Filter* filter = NULL;
     if (Filter::filter_type() == filter_type &&
         Filter::IsMediaFormatSupported(media_format)) {
@@ -142,7 +142,7 @@ class FilterFactoryImpl1 : public FilterFactory {
 
  protected:
   virtual MediaFilter* Create(FilterType filter_type,
-                              const MediaFormat* media_format) {
+                              const MediaFormat& media_format) {
     Filter* filter = NULL;
     if (Filter::filter_type() == filter_type &&
         Filter::IsMediaFormatSupported(media_format)) {
@@ -178,7 +178,7 @@ class InstanceFilterFactory : public FilterFactory {
 
  protected:
   virtual MediaFilter* Create(FilterType filter_type,
-                              const MediaFormat* media_format) {
+                              const MediaFormat& media_format) {
     if (Filter::filter_type() == filter_type &&
         Filter::IsMediaFormatSupported(media_format)) {
       if (!create_called_) {
diff --git a/media/base/filters.h b/media/base/filters.h
index 7ceb9e8..6290e28 100644
--- a/media/base/filters.h
+++ b/media/base/filters.h
@@ -97,9 +97,9 @@ class DataSource : public MediaFilter {
     return FILTER_DATA_SOURCE;
   }
 
-  static bool IsMediaFormatSupported(const MediaFormat* media_format) {
+  static bool IsMediaFormatSupported(const MediaFormat& media_format) {
     std::string mime_type;
-    return (media_format->GetAsString(MediaFormat::kMimeType, &mime_type) &&
+    return (media_format.GetAsString(MediaFormat::kMimeType, &mime_type) &&
             mime_type == mime_type::kURL);
   }
 
@@ -109,7 +109,7 @@ class DataSource : public MediaFilter {
   virtual bool Initialize(const std::string& url) = 0;
 
   // Returns the MediaFormat for this filter.
-  virtual const MediaFormat* GetMediaFormat() = 0;
+  virtual const MediaFormat& media_format() = 0;
 
   // Read the given amount of bytes into data, returns the number of bytes read
   // if successful, kReadError otherwise.
@@ -134,9 +134,9 @@ class Demuxer : public MediaFilter {
     return FILTER_DEMUXER;
   }
 
-  static bool IsMediaFormatSupported(const MediaFormat* media_format) {
+  static bool IsMediaFormatSupported(const MediaFormat& media_format) {
     std::string mime_type;
-    return (media_format->GetAsString(MediaFormat::kMimeType, &mime_type) &&
+    return (media_format.GetAsString(MediaFormat::kMimeType, &mime_type) &&
             mime_type == mime_type::kApplicationOctetStream);
   }
 
@@ -154,7 +154,7 @@ class Demuxer : public MediaFilter {
 class DemuxerStream : public base::RefCountedThreadSafe<DemuxerStream> {
  public:
   // Returns the MediaFormat for this filter.
-  virtual const MediaFormat* GetMediaFormat() = 0;
+  virtual const MediaFormat& media_format() = 0;
 
   // Schedules a read and takes ownership of the given buffer.
   virtual void Read(Assignable<Buffer>* buffer) = 0;
@@ -198,7 +198,7 @@ class VideoDecoder : public MediaFilter {
   virtual bool Initialize(DemuxerStream* demuxer_stream) = 0;
 
   // Returns the MediaFormat for this filter.
-  virtual const MediaFormat* GetMediaFormat() = 0;
+  virtual const MediaFormat& media_format() = 0;
 
   // Schedules a read and takes ownership of the given buffer.
   virtual void Read(Assignable<VideoFrame>* video_frame) = 0;
@@ -219,7 +219,7 @@ class AudioDecoder : public MediaFilter {
   virtual bool Initialize(DemuxerStream* demuxer_stream) = 0;
 
   // Returns the MediaFormat for this filter.
-  virtual const MediaFormat* GetMediaFormat() = 0;
+  virtual const MediaFormat& media_format() = 0;
 
   // Schedules a read and takes ownership of the given buffer.
   virtual void Read(Assignable<Buffer>* buffer) = 0;
diff --git a/media/base/mock_media_filters.h b/media/base/mock_media_filters.h
index 4f12c00..4695a65 100644
--- a/media/base/mock_media_filters.h
+++ b/media/base/mock_media_filters.h
@@ -124,8 +124,8 @@ class MockDataSource : public DataSource {
     }
   }
 
-  virtual const MediaFormat* GetMediaFormat() {
-    return &media_format_;
+  virtual const MediaFormat& media_format() {
+    return media_format_;
   }
 
   virtual size_t Read(uint8* data, size_t size) {
@@ -210,8 +210,8 @@ class MockDemuxerStream : public DemuxerStream {
   }
 
   // Implementation of DemuxerStream.
-  virtual const MediaFormat* GetMediaFormat() {
-    return &media_format_;
+  virtual const MediaFormat& media_format() {
+    return media_format_;
   }
 
   virtual void Read(Assignable<Buffer>* buffer) {
@@ -299,7 +299,7 @@ class MockAudioDecoder : public AudioDecoder {
                                   const MockFilterConfig*>(config);
   }
 
-  static bool IsMediaFormatSupported(const MediaFormat* media_format) {
+  static bool IsMediaFormatSupported(const MediaFormat& media_format) {
     return true;  // TODO(ralphl): check for a supported format.
   }
 
@@ -317,8 +317,8 @@ class MockAudioDecoder : public AudioDecoder {
     return true;
   }
 
-  virtual const MediaFormat* GetMediaFormat() {
-    return &media_format_;
+  virtual const MediaFormat& media_format() {
+    return media_format_;
   }
 
   virtual void Read(Assignable<Buffer>* buffer) {
@@ -343,7 +343,7 @@ class MockAudioRenderer : public AudioRenderer {
                                   const MockFilterConfig*>(config);
   }
 
-  static bool IsMediaFormatSupported(const MediaFormat* media_format) {
+  static bool IsMediaFormatSupported(const MediaFormat& media_format) {
     return true;  // TODO(ralphl): check for a supported format
   }
 
@@ -375,7 +375,7 @@ class MockVideoDecoder : public VideoDecoder {
                                   const MockFilterConfig*>(config);
   }
 
-  static bool IsMediaFormatSupported(const MediaFormat* media_format) {
+  static bool IsMediaFormatSupported(const MediaFormat& media_format) {
     return true;  // TODO(ralphl): check for a supported format.
   }
 
@@ -425,8 +425,8 @@ class MockVideoDecoder : public VideoDecoder {
     return true;
   }
 
-  virtual const MediaFormat* GetMediaFormat() {
-    return &media_format_;
+  virtual const MediaFormat& media_format() {
+    return media_format_;
   }
 
   virtual void Read(Assignable<VideoFrame>* buffer) {
@@ -482,7 +482,7 @@ class MockVideoRenderer : public VideoRenderer {
                                   const MockFilterConfig*>(config);
   }
 
-  static bool IsMediaFormatSupported(const MediaFormat* media_format) {
+  static bool IsMediaFormatSupported(const MediaFormat& media_format) {
     return true;  // TODO(ralphl): check for a supported format
   }
 
diff --git a/media/base/pipeline_impl.cc b/media/base/pipeline_impl.cc
index 3e3a40d..a36da6c 100644
--- a/media/base/pipeline_impl.cc
+++ b/media/base/pipeline_impl.cc
@@ -418,13 +418,12 @@ void PipelineThread::Render(FilterFactory* filter_factory, Demuxer* demuxer) {
   const std::string major_mime_type = Decoder::major_mime_type();
   const int num_outputs = demuxer->GetNumberOfStreams();
   for (int i = 0; i < num_outputs; ++i) {
-    scoped_refptr<DemuxerStream> demuxer_stream = demuxer->GetStream(i);
-    const MediaFormat* stream_format = demuxer_stream->GetMediaFormat();
+    scoped_refptr<DemuxerStream> stream = demuxer->GetStream(i);
     std::string value;
-    if (stream_format->GetAsString(MediaFormat::kMimeType, &value) &&
+    if (stream->media_format().GetAsString(MediaFormat::kMimeType, &value) &&
         0 == value.compare(0, major_mime_type.length(), major_mime_type)) {
       scoped_refptr<Decoder> decoder =
-          CreateFilter<Decoder, DemuxerStream>(filter_factory, demuxer_stream);
+          CreateFilter<Decoder, DemuxerStream>(filter_factory, stream);
       if (PipelineOk()) {
         DCHECK(decoder);
         CreateFilter<Renderer, Decoder>(filter_factory, decoder);
@@ -500,7 +499,7 @@ template <class Filter, class Source>
 scoped_refptr<Filter> PipelineThread::CreateFilter(
     FilterFactory* filter_factory,
     Source source,
-    const MediaFormat* media_format) {
+    const MediaFormat& media_format) {
   DCHECK(PipelineOk());
   scoped_refptr<Filter> filter = filter_factory->Create<Filter>(media_format);
   if (!filter) {
@@ -549,7 +548,7 @@ scoped_refptr<DataSource> PipelineThread::CreateDataSource(
   MediaFormat url_format;
   url_format.SetAsString(MediaFormat::kMimeType, mime_type::kURL);
   url_format.SetAsString(MediaFormat::kURL, url);
-  return CreateFilter<DataSource>(filter_factory, url, &url_format);
+  return CreateFilter<DataSource>(filter_factory, url, url_format);
 }
 
 // Called as a result of destruction of the thread.
diff --git a/media/base/pipeline_impl.h b/media/base/pipeline_impl.h
index a5b8c0e..c4c4393 100644
--- a/media/base/pipeline_impl.h
+++ b/media/base/pipeline_impl.h
@@ -266,7 +266,7 @@ class PipelineThread : public base::RefCountedThreadSafe<PipelineThread>,
   template <class Filter, class Source>
   scoped_refptr<Filter> CreateFilter(FilterFactory* filter_factory,
                                      Source source,
-                                     const MediaFormat* source_media_format);
+                                     const MediaFormat& source_media_format);
 
   // Creates a Filter and initilizes it with the given |source|.  If a Filter
   // could not be created or an error occurred, this metod returns NULL and the
@@ -278,7 +278,7 @@ class PipelineThread : public base::RefCountedThreadSafe<PipelineThread>,
                                      Source* source) {
     return CreateFilter<Filter, Source*>(filter_factory,
                                          source,
-                                         source->GetMediaFormat());
+                                         source->media_format());
   }
 
   // Creates a DataSource (the first filter in a pipeline), and initializes it
diff --git a/media/filters/audio_renderer_base.cc b/media/filters/audio_renderer_base.cc
index 880ca37..a444ba6 100644
--- a/media/filters/audio_renderer_base.cc
+++ b/media/filters/audio_renderer_base.cc
@@ -52,7 +52,7 @@ bool AudioRendererBase::Initialize(AudioDecoder* decoder) {
   }
 
   // Defer initialization until all scheduled reads have completed.
-  return OnInitialize(decoder_->GetMediaFormat());
+  return OnInitialize(decoder_->media_format());
 }
 
 void AudioRendererBase::OnAssignment(Buffer* buffer_in) {
@@ -138,16 +138,16 @@ void AudioRendererBase::ScheduleRead() {
 }
 
 // static
-bool AudioRendererBase::ParseMediaFormat(const MediaFormat* media_format,
+bool AudioRendererBase::ParseMediaFormat(const MediaFormat& media_format,
                                          int* channels_out,
                                          int* sample_rate_out,
                                          int* sample_bits_out) {
   // TODO(scherkus): might be handy to support NULL parameters.
   std::string mime_type;
-  return media_format->GetAsString(MediaFormat::kMimeType, &mime_type) &&
-      media_format->GetAsInteger(MediaFormat::kChannels, channels_out) &&
-      media_format->GetAsInteger(MediaFormat::kSampleRate, sample_rate_out) &&
-      media_format->GetAsInteger(MediaFormat::kSampleBits, sample_bits_out) &&
+  return media_format.GetAsString(MediaFormat::kMimeType, &mime_type) &&
+      media_format.GetAsInteger(MediaFormat::kChannels, channels_out) &&
+      media_format.GetAsInteger(MediaFormat::kSampleRate, sample_rate_out) &&
+      media_format.GetAsInteger(MediaFormat::kSampleBits, sample_bits_out) &&
       mime_type.compare(mime_type::kUncompressedAudio) == 0;
 }
 
diff --git a/media/filters/audio_renderer_base.h b/media/filters/audio_renderer_base.h
index fd371e6..6553b12 100644
--- a/media/filters/audio_renderer_base.h
+++ b/media/filters/audio_renderer_base.h
@@ -43,13 +43,13 @@ class AudioRendererBase : public AudioRenderer {
   static const size_t kDefaultMaxQueueSize;
 
   // Only allow a factory to create this class.
-  AudioRendererBase(size_t max_queue_size);
+  explicit AudioRendererBase(size_t max_queue_size);
   virtual ~AudioRendererBase();
 
   // Called by Initialize().  |media_format| is the format of the AudioDecoder.
   // Subclasses should return true if they were able to initialize, false
   // otherwise.
-  virtual bool OnInitialize(const MediaFormat* media_format) = 0;
+  virtual bool OnInitialize(const MediaFormat& media_format) = 0;
 
   // Called by Stop().  Subclasses should perform any necessary cleanup during
   // this time, such as stopping any running threads.
@@ -70,7 +70,7 @@ class AudioRendererBase : public AudioRenderer {
 
   // Helper to parse a media format and return whether we were successful
   // retrieving all the information we care about.
-  static bool ParseMediaFormat(const MediaFormat* media_format,
+  static bool ParseMediaFormat(const MediaFormat& media_format,
                                int* channels_out, int* sample_rate_out,
                                int* sample_bits_out);
 
diff --git a/media/filters/audio_renderer_impl.cc b/media/filters/audio_renderer_impl.cc
index 7b66e14..55a1096 100644
--- a/media/filters/audio_renderer_impl.cc
+++ b/media/filters/audio_renderer_impl.cc
@@ -25,7 +25,7 @@ AudioRendererImpl::~AudioRendererImpl() {
 }
 
 bool AudioRendererImpl::IsMediaFormatSupported(
-    const MediaFormat* media_format) {
+    const MediaFormat& media_format) {
   int channels;
   int sample_rate;
   int sample_bits;
@@ -66,7 +66,7 @@ void AudioRendererImpl::OnError(AudioOutputStream* stream, int code) {
   NOTIMPLEMENTED();
 }
 
-bool AudioRendererImpl::OnInitialize(const MediaFormat* media_format) {
+bool AudioRendererImpl::OnInitialize(const MediaFormat& media_format) {
   // Parse out audio parameters.
   int channels;
   int sample_rate;
diff --git a/media/filters/audio_renderer_impl.h b/media/filters/audio_renderer_impl.h
index 85ebca0..b7e551b 100644
--- a/media/filters/audio_renderer_impl.h
+++ b/media/filters/audio_renderer_impl.h
@@ -29,7 +29,7 @@ class AudioRendererImpl : public AudioRendererBase,
     return new FilterFactoryImpl0<AudioRendererImpl>();
   }
 
-  static bool IsMediaFormatSupported(const MediaFormat* media_format);
+  static bool IsMediaFormatSupported(const MediaFormat& media_format);
 
   // MediaFilter implementation.
   virtual void SetPlaybackRate(float playback_rate);
@@ -49,7 +49,7 @@ class AudioRendererImpl : public AudioRendererBase,
   virtual ~AudioRendererImpl();
 
   // AudioRendererBase implementation.
-  virtual bool OnInitialize(const MediaFormat* media_format);
+  virtual bool OnInitialize(const MediaFormat& media_format);
   virtual void OnStop();
 
  private:
diff --git a/media/filters/decoder_base.h b/media/filters/decoder_base.h
index 685495d..adecbf2 100644
--- a/media/filters/decoder_base.h
+++ b/media/filters/decoder_base.h
@@ -58,7 +58,7 @@ class DecoderBase : public Decoder {
     }
   }
 
-  virtual const MediaFormat* GetMediaFormat() { return &media_format_; }
+  virtual const MediaFormat& media_format() { return media_format_; }
 
   // Audio or Video decoder.
   virtual void Read(Assignable<Output>* output) {
diff --git a/media/filters/ffmpeg_audio_decoder.cc b/media/filters/ffmpeg_audio_decoder.cc
index 378d865..74559d3 100644
--- a/media/filters/ffmpeg_audio_decoder.cc
+++ b/media/filters/ffmpeg_audio_decoder.cc
@@ -16,7 +16,7 @@ FFmpegAudioDecoder::~FFmpegAudioDecoder() {
 }
 
 // static
-bool FFmpegAudioDecoder::IsMediaFormatSupported(const MediaFormat* format) {
+bool FFmpegAudioDecoder::IsMediaFormatSupported(const MediaFormat& format) {
   NOTIMPLEMENTED();
   return false;
 }
diff --git a/media/filters/ffmpeg_audio_decoder.h b/media/filters/ffmpeg_audio_decoder.h
index 9df354b..52ffde9 100644
--- a/media/filters/ffmpeg_audio_decoder.h
+++ b/media/filters/ffmpeg_audio_decoder.h
@@ -19,7 +19,7 @@ class FFmpegAudioDecoder : public DecoderBase<AudioDecoder, Buffer> {
     return new FilterFactoryImpl0<FFmpegAudioDecoder>();
   }
 
-  static bool IsMediaFormatSupported(const MediaFormat* media_format);
+  static bool IsMediaFormatSupported(const MediaFormat& media_format);
 
   virtual bool OnInitialize(DemuxerStream* demuxer_stream);
 
diff --git a/media/filters/ffmpeg_demuxer.cc b/media/filters/ffmpeg_demuxer.cc
index 5fce5a4..0446325 100644
--- a/media/filters/ffmpeg_demuxer.cc
+++ b/media/filters/ffmpeg_demuxer.cc
@@ -123,8 +123,8 @@ void FFmpegDemuxerStream::EnqueuePacket(AVPacket* packet) {
   FulfillPendingReads();
 }
 
-const MediaFormat* FFmpegDemuxerStream::GetMediaFormat() {
-  return &media_format_;
+const MediaFormat& FFmpegDemuxerStream::media_format() {
+  return media_format_;
 }
 
 void FFmpegDemuxerStream::Read(Assignable<Buffer>* buffer) {
diff --git a/media/filters/ffmpeg_demuxer.h b/media/filters/ffmpeg_demuxer.h
index 317969d..dea349d 100644
--- a/media/filters/ffmpeg_demuxer.h
+++ b/media/filters/ffmpeg_demuxer.h
@@ -57,7 +57,7 @@ class FFmpegDemuxerStream : public DemuxerStream {
   base::TimeDelta duration() { return duration_; }
 
   // DemuxerStream implementation.
-  virtual const MediaFormat* GetMediaFormat();
+  virtual const MediaFormat& media_format();
   virtual void Read(Assignable<Buffer>* buffer);
 
   AVStream* av_stream() {
diff --git a/media/filters/ffmpeg_demuxer_unittest.cc b/media/filters/ffmpeg_demuxer_unittest.cc
index b37196d..aeba6fe 100644
--- a/media/filters/ffmpeg_demuxer_unittest.cc
+++ b/media/filters/ffmpeg_demuxer_unittest.cc
@@ -148,12 +148,12 @@ TEST(FFmpegDemuxerTest, InitializeFailure) {
   // Should only accept application/octet-stream type.
   MediaFormat media_format;
   media_format.SetAsString(MediaFormat::kMimeType, "foo/x-bar");
-  scoped_refptr<Demuxer> demuxer(factory->Create<Demuxer>(&media_format));
+  scoped_refptr<Demuxer> demuxer(factory->Create<Demuxer>(media_format));
   ASSERT_FALSE(demuxer);
   media_format.Clear();
   media_format.SetAsString(MediaFormat::kMimeType,
                            mime_type::kApplicationOctetStream);
-  demuxer = factory->Create<Demuxer>(&media_format);
+  demuxer = factory->Create<Demuxer>(media_format);
   ASSERT_TRUE(demuxer);
 
   // Prepare a filter host and data source for the demuxer.
@@ -173,7 +173,7 @@ TEST(FFmpegDemuxerTest, InitializeFailure) {
   // Simulate av_find_stream_info failing.
   g_av_open_input_file = 0;
   g_av_find_stream_info = AVERROR_IO;
-  demuxer = factory->Create<Demuxer>(&media_format);
+  demuxer = factory->Create<Demuxer>(media_format);
   filter_host.reset(new MockFilterHost<Demuxer>(&pipeline, demuxer));
   EXPECT_FALSE(demuxer->Initialize(data_source));
   EXPECT_FALSE(filter_host->IsInitialized());
@@ -181,7 +181,7 @@ TEST(FFmpegDemuxerTest, InitializeFailure) {
 
   // Simulate media with no parseable streams.
   InitializeFFmpegMocks();
-  demuxer = factory->Create<Demuxer>(&media_format);
+  demuxer = factory->Create<Demuxer>(media_format);
   filter_host.reset(new MockFilterHost<Demuxer>(&pipeline, demuxer));
   EXPECT_FALSE(demuxer->Initialize(data_source));
   EXPECT_FALSE(filter_host->IsInitialized());
@@ -192,7 +192,7 @@ TEST(FFmpegDemuxerTest, InitializeFailure) {
   g_format.streams[0] = &g_streams[0];
   g_streams[0].codec = &g_data_codec;
   g_streams[0].duration = 10;
-  demuxer = factory->Create<Demuxer>(&media_format);
+  demuxer = factory->Create<Demuxer>(media_format);
   filter_host.reset(new MockFilterHost<Demuxer>(&pipeline, demuxer));
   EXPECT_FALSE(demuxer->Initialize(data_source));
   EXPECT_FALSE(filter_host->IsInitialized());
@@ -226,7 +226,7 @@ TEST(FFmpegDemuxerTest, InitializeStreams) {
   // Create our demuxer.
   scoped_refptr<FilterFactory> factory = FFmpegDemuxer::CreateFilterFactory();
   scoped_refptr<Demuxer> demuxer
-      = factory->Create<Demuxer>(data_source->GetMediaFormat());
+      = factory->Create<Demuxer>(data_source->media_format());
   EXPECT_TRUE(demuxer);
   MockFilterHost<Demuxer> filter_host_b(&pipeline, demuxer);
   EXPECT_TRUE(demuxer->Initialize(data_source));
@@ -243,29 +243,35 @@ TEST(FFmpegDemuxerTest, InitializeStreams) {
   // First stream should be video.
   scoped_refptr<DemuxerStream> stream = demuxer->GetStream(0);
   ASSERT_TRUE(stream);
-  const MediaFormat* stream_format = stream->GetMediaFormat();
   std::string mime_type;
   int result;
-  EXPECT_TRUE(stream_format->GetAsString(MediaFormat::kMimeType, &mime_type));
+  EXPECT_TRUE(
+      stream->media_format().GetAsString(MediaFormat::kMimeType, &mime_type));
   EXPECT_STREQ(mime_type::kFFmpegVideo, mime_type.c_str());
-  EXPECT_TRUE(stream_format->GetAsInteger(kFFmpegCodecID, &result));
+  EXPECT_TRUE(
+      stream->media_format().GetAsInteger(kFFmpegCodecID, &result));
   EXPECT_EQ(CODEC_ID_THEORA, static_cast<CodecID>(result));
-  EXPECT_TRUE(stream_format->GetAsInteger(MediaFormat::kHeight, &result));
+  EXPECT_TRUE(
+      stream->media_format().GetAsInteger(MediaFormat::kHeight, &result));
   EXPECT_EQ(g_video_codec.height, result);
-  EXPECT_TRUE(stream_format->GetAsInteger(MediaFormat::kWidth, &result));
+  EXPECT_TRUE(
+      stream->media_format().GetAsInteger(MediaFormat::kWidth, &result));
   EXPECT_EQ(g_video_codec.width, result);
 
   // Second stream should be audio.
   stream = demuxer->GetStream(1);
   ASSERT_TRUE(stream);
-  stream_format = stream->GetMediaFormat();
-  EXPECT_TRUE(stream_format->GetAsString(MediaFormat::kMimeType, &mime_type));
+  EXPECT_TRUE(
+      stream->media_format().GetAsString(MediaFormat::kMimeType, &mime_type));
   EXPECT_STREQ(mime_type::kFFmpegAudio, mime_type.c_str());
-  EXPECT_TRUE(stream_format->GetAsInteger(kFFmpegCodecID, &result));
+  EXPECT_TRUE(
+      stream->media_format().GetAsInteger(kFFmpegCodecID, &result));
   EXPECT_EQ(CODEC_ID_VORBIS, static_cast<CodecID>(result));
-  EXPECT_TRUE(stream_format->GetAsInteger(MediaFormat::kChannels, &result));
+  EXPECT_TRUE(
+      stream->media_format().GetAsInteger(MediaFormat::kChannels, &result));
   EXPECT_EQ(g_audio_codec.channels, result);
-  EXPECT_TRUE(stream_format->GetAsInteger(MediaFormat::kSampleRate, &result));
+  EXPECT_TRUE(
+      stream->media_format().GetAsInteger(MediaFormat::kSampleRate, &result));
   EXPECT_EQ(g_audio_codec.sample_rate, result);
 }
 
@@ -300,7 +306,7 @@ TEST(FFmpegDemuxerTest, Read) {
   // Create our demuxer.
   scoped_refptr<FilterFactory> factory = FFmpegDemuxer::CreateFilterFactory();
   scoped_refptr<Demuxer> demuxer
-      = factory->Create<Demuxer>(data_source->GetMediaFormat());
+      = factory->Create<Demuxer>(data_source->media_format());
   EXPECT_TRUE(demuxer);
   MockFilterHost<Demuxer> filter_host_b(&pipeline, demuxer);
   EXPECT_TRUE(demuxer->Initialize(data_source));
@@ -335,7 +341,7 @@ TEST(FFmpegDemuxerTest, Read) {
   pipeline.RunAllTasks();
   EXPECT_TRUE(buffer->assigned());
   EXPECT_TRUE(buffer->buffer());
-  EXPECT_EQ(audio_data, (uint8*)buffer->buffer()->GetData());
+  EXPECT_EQ(audio_data, buffer->buffer()->GetData());
   EXPECT_EQ(kDataSize, buffer->buffer()->GetDataSize());
 
   // Prepare our test video packet.
@@ -349,7 +355,7 @@ TEST(FFmpegDemuxerTest, Read) {
   pipeline.RunAllTasks();
   EXPECT_TRUE(buffer->assigned());
   EXPECT_TRUE(buffer->buffer());
-  EXPECT_EQ(video_data, (uint8*)buffer->buffer()->GetData());
+  EXPECT_EQ(video_data, buffer->buffer()->GetData());
   EXPECT_EQ(kDataSize, buffer->buffer()->GetDataSize());
 
   // Simulate end of stream.
diff --git a/media/filters/ffmpeg_video_decoder.cc b/media/filters/ffmpeg_video_decoder.cc
index dad8b88..f429ea6 100644
--- a/media/filters/ffmpeg_video_decoder.cc
+++ b/media/filters/ffmpeg_video_decoder.cc
@@ -16,7 +16,7 @@ FFmpegVideoDecoder::~FFmpegVideoDecoder() {
 }
 
 // static
-bool FFmpegVideoDecoder::IsMediaFormatSupported(const MediaFormat* format) {
+bool FFmpegVideoDecoder::IsMediaFormatSupported(const MediaFormat& format) {
   NOTIMPLEMENTED();
   return false;
 }
diff --git a/media/filters/ffmpeg_video_decoder.h b/media/filters/ffmpeg_video_decoder.h
index 7e9fb91..a047823 100644
--- a/media/filters/ffmpeg_video_decoder.h
+++ b/media/filters/ffmpeg_video_decoder.h
@@ -19,7 +19,7 @@ class FFmpegVideoDecoder : public DecoderBase<VideoDecoder, VideoFrame> {
     return new FilterFactoryImpl0<FFmpegVideoDecoder>();
   }
 
-  static bool IsMediaFormatSupported(const MediaFormat* media_format);
+  static bool IsMediaFormatSupported(const MediaFormat& media_format);
 
   virtual bool OnInitialize(DemuxerStream* demuxer_stream);
 
diff --git a/media/filters/file_data_source.cc b/media/filters/file_data_source.cc
index 854fea2..c622c04 100644
--- a/media/filters/file_data_source.cc
+++ b/media/filters/file_data_source.cc
@@ -53,8 +53,8 @@ void FileDataSource::Stop() {
   }
 }
 
-const MediaFormat* FileDataSource::GetMediaFormat() {
-  return &media_format_;
+const MediaFormat& FileDataSource::media_format() {
+  return media_format_;
 }
 
 size_t FileDataSource::Read(uint8* data, size_t size) {
diff --git a/media/filters/file_data_source.h b/media/filters/file_data_source.h
index 1c03cf0..c7bfdfd 100644
--- a/media/filters/file_data_source.h
+++ b/media/filters/file_data_source.h
@@ -29,7 +29,7 @@ class FileDataSource : public DataSource {
 
   // Implementation of DataSource.
   virtual bool Initialize(const std::string& url);
-  virtual const MediaFormat* GetMediaFormat();
+  virtual const MediaFormat& media_format();
   virtual size_t Read(uint8* data, size_t size);
   virtual bool GetPosition(int64* position_out);
   virtual bool SetPosition(int64 position);
diff --git a/media/filters/file_data_source_unittest.cc b/media/filters/file_data_source_unittest.cc
index 2545e7c..8512300 100644
--- a/media/filters/file_data_source_unittest.cc
+++ b/media/filters/file_data_source_unittest.cc
@@ -88,7 +88,7 @@ TEST(FileDataSourceTest, ReadData) {
 
   // Create our data source.
   scoped_refptr<FilterFactory> factory = FileDataSource::CreateFactory();
-  FileDataSource* filter = factory->Create<FileDataSource>(&url_format);
+  FileDataSource* filter = factory->Create<FileDataSource>(url_format);
   EXPECT_TRUE(filter);
 
   // Create our mock pipeline and filter host and initialize the data source.
diff --git a/media/filters/null_audio_renderer.cc b/media/filters/null_audio_renderer.cc
index f30ed59..1d50e69 100644
--- a/media/filters/null_audio_renderer.cc
+++ b/media/filters/null_audio_renderer.cc
@@ -29,7 +29,7 @@ NullAudioRenderer::~NullAudioRenderer() {
 
 // static
 bool NullAudioRenderer::IsMediaFormatSupported(
-    const MediaFormat* media_format) {
+    const MediaFormat& media_format) {
   int channels;
   int sample_rate;
   int sample_bits;
@@ -63,7 +63,7 @@ void NullAudioRenderer::ThreadMain() {
   }
 }
 
-bool NullAudioRenderer::OnInitialize(const MediaFormat* media_format) {
+bool NullAudioRenderer::OnInitialize(const MediaFormat& media_format) {
   // Parse out audio parameters.
   int channels;
   int sample_rate;
diff --git a/media/filters/null_audio_renderer.h b/media/filters/null_audio_renderer.h
index cf66648..824e13d 100644
--- a/media/filters/null_audio_renderer.h
+++ b/media/filters/null_audio_renderer.h
@@ -37,7 +37,7 @@ class NullAudioRenderer : public AudioRendererBase, PlatformThread::Delegate {
   }
 
   // Compatible with any audio/x-uncompressed MediaFormat.
-  static bool IsMediaFormatSupported(const MediaFormat* media_format);
+  static bool IsMediaFormatSupported(const MediaFormat& media_format);
 
   // MediaFilter implementation.
   virtual void SetPlaybackRate(float playback_rate);
@@ -55,7 +55,7 @@ class NullAudioRenderer : public AudioRendererBase, PlatformThread::Delegate {
   virtual ~NullAudioRenderer();
 
   // AudioRendererBase implementation.
-  virtual bool OnInitialize(const MediaFormat* media_format);
+  virtual bool OnInitialize(const MediaFormat& media_format);
   virtual void OnStop();
 
  private:
diff --git a/media/filters/test_video_decoder.h b/media/filters/test_video_decoder.h
index 3ca6a3f..84d6e66 100644
--- a/media/filters/test_video_decoder.h
+++ b/media/filters/test_video_decoder.h
@@ -25,13 +25,13 @@ class TestVideoDecoder : public DecoderBase<VideoDecoder, VideoFrame> {
   }
 
   bool OnInitialize(DemuxerStream* demuxer_stream) {
-    const MediaFormat* media_format = demuxer_stream->GetMediaFormat();
+    const MediaFormat& media_format = demuxer_stream->media_format();
     std::string mime_type;
     int width, height;
-    if (media_format->GetAsString(MediaFormat::kMimeType, &mime_type) &&
+    if (media_format.GetAsString(MediaFormat::kMimeType, &mime_type) &&
         mime_type.compare(mime_type::kH264AnnexB) == 0 &&
-        media_format->GetAsInteger(MediaFormat::kWidth, &width) &&
-        media_format->GetAsInteger(MediaFormat::kHeight, &height)) {
+        media_format.GetAsInteger(MediaFormat::kWidth, &width) &&
+        media_format.GetAsInteger(MediaFormat::kHeight, &height)) {
       video_width_ = width;
       video_height_ = height;
       media_format_.SetAsString(MediaFormat::kMimeType,
@@ -59,9 +59,9 @@ class TestVideoDecoder : public DecoderBase<VideoDecoder, VideoFrame> {
     }
   }
 
-  static bool IsMediaFormatSupported(const MediaFormat* media_format) {
+  static bool IsMediaFormatSupported(const MediaFormat& media_format) {
     std::string mime_type;
-    return (media_format->GetAsString(MediaFormat::kMimeType, &mime_type) &&
+    return (media_format.GetAsString(MediaFormat::kMimeType, &mime_type) &&
             mime_type == mime_type::kH264AnnexB);
   }
 
diff --git a/media/filters/test_video_renderer.h b/media/filters/test_video_renderer.h
index f6c3c22..f9535f2 100644
--- a/media/filters/test_video_renderer.h
+++ b/media/filters/test_video_renderer.h
@@ -46,7 +46,7 @@ class TestVideoRenderer : public VideoRendererBase {
   size_t paint_called() { return paint_called_; }
   base::TimeDelta last_timestamp() { return last_timestamp_; }
 
-  static bool IsMediaFormatSupported(const MediaFormat* format) {
+  static bool IsMediaFormatSupported(const MediaFormat& format) {
     return VideoRendererBase::IsMediaFormatSupported(format);
   }
 
diff --git a/media/filters/video_renderer_base.cc b/media/filters/video_renderer_base.cc
index 57caf99..744942f 100644
--- a/media/filters/video_renderer_base.cc
+++ b/media/filters/video_renderer_base.cc
@@ -45,22 +45,22 @@ VideoRendererBase::~VideoRendererBase() {
 
 // static
 bool VideoRendererBase::IsMediaFormatSupported(
-    const MediaFormat* media_format) {
+    const MediaFormat& media_format) {
   int width;
   int height;
   return ParseMediaFormat(media_format, &width, &height);
 }
 
 // static
-bool VideoRendererBase::ParseMediaFormat(const MediaFormat* media_format,
+bool VideoRendererBase::ParseMediaFormat(const MediaFormat& media_format,
                                          int* width_out,
                                          int* height_out) {
-  DCHECK(media_format && width_out && height_out);
+  DCHECK(width_out && height_out);
   std::string mime_type;
-  return (media_format->GetAsString(MediaFormat::kMimeType, &mime_type) &&
+  return (media_format.GetAsString(MediaFormat::kMimeType, &mime_type) &&
           mime_type.compare(mime_type::kUncompressedVideo) == 0 &&
-          media_format->GetAsInteger(MediaFormat::kWidth, width_out) &&
-          media_format->GetAsInteger(MediaFormat::kHeight, height_out));
+          media_format.GetAsInteger(MediaFormat::kWidth, width_out) &&
+          media_format.GetAsInteger(MediaFormat::kHeight, height_out));
 }
 
 void VideoRendererBase::Stop() {
@@ -82,7 +82,7 @@ void VideoRendererBase::Stop() {
 bool VideoRendererBase::Initialize(VideoDecoder* decoder) {
   int width, height;
   decoder_ = decoder;
-  if (ParseMediaFormat(decoder_->GetMediaFormat(), &width, &height) &&
+  if (ParseMediaFormat(decoder_->media_format(), &width, &height) &&
       OnInitialize(width, height)) {
     host_->SetVideoSize(width, height);
     host_->SetTimeUpdateCallback(
diff --git a/media/filters/video_renderer_base.h b/media/filters/video_renderer_base.h
index 16566fc..2c51895 100644
--- a/media/filters/video_renderer_base.h
+++ b/media/filters/video_renderer_base.h
@@ -85,12 +85,12 @@ class VideoRendererBase : public VideoRenderer {
   void GetCurrentFrame(scoped_refptr<VideoFrame>* frame_out);
 
   // Answers question from the factory to see if we accept |format|.
-  static bool IsMediaFormatSupported(const MediaFormat* format);
+  static bool IsMediaFormatSupported(const MediaFormat& format);
 
   // Used by the IsMediaFormatSupported and Initialize methods.  Examines the
   // |media_format| and returns true if the format is supported.  Both output
   // parameters, |width_out| and |height_out| are required and must not be NULL.
-  static bool ParseMediaFormat(const MediaFormat* media_format,
+  static bool ParseMediaFormat(const MediaFormat& media_format,
                                int* width_out,
                                int* height_out);