WeakPtr destruction order cleanup: media edition.

Per WeakPtrFactory documentation it must be the first member variable
destructed to avoid invalid member variable access during destruction.

Additional cleanups:
- Removes "weak_this_" usage when there is no manual factory invalidation.
- Adds DISALLOW_COPY_AND_ASSIGN to SendProcess.
- Removes unused WeakPtr from FFmpegVideoDecoder, VpxVideoDecoder, FFMpegAudioDecoder, OpusAudioDecoder

BUG=351048
TEST=compiles, passes CQ.
R=fischman@chromium.org

Review URL: https://codereview.chromium.org/193303002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@257765 0039d316-1c4b-4281-b951-d872f2087c98

4 files changed, 14 insertions, 11 deletions

diff --git a/media/audio/alsa/alsa_input.cc b/media/audio/alsa/alsa_input.cc
index bf31f51..9cde236 100644
--- a/media/audio/alsa/alsa_input.cc
+++ b/media/audio/alsa/alsa_input.cc
@@ -32,7 +32,8 @@ AlsaPcmInputStream::AlsaPcmInputStream(AudioManagerBase* audio_manager,
       device_name_(device_name),
       params_(params),
       bytes_per_buffer_(params.frames_per_buffer() *
-                        (params.channels() * params.bits_per_sample()) / 8),
+                        (params.channels() * params.bits_per_sample()) /
+                        8),
       wrapper_(wrapper),
       buffer_duration_(base::TimeDelta::FromMicroseconds(
           params.frames_per_buffer() * base::Time::kMicrosecondsPerSecond /
@@ -41,9 +42,8 @@ AlsaPcmInputStream::AlsaPcmInputStream(AudioManagerBase* audio_manager,
       device_handle_(NULL),
       mixer_handle_(NULL),
       mixer_element_handle_(NULL),
-      weak_factory_(this),
-      read_callback_behind_schedule_(false) {
-}
+      read_callback_behind_schedule_(false),
+      weak_factory_(this) {}
 
 AlsaPcmInputStream::~AlsaPcmInputStream() {}
 
diff --git a/media/audio/alsa/alsa_input.h b/media/audio/alsa/alsa_input.h
index 6e9aad90..90c3883 100644
--- a/media/audio/alsa/alsa_input.h
+++ b/media/audio/alsa/alsa_input.h
@@ -80,10 +80,12 @@ class AlsaPcmInputStream : public AgcAudioStream<AudioInputStream> {
   snd_pcm_t* device_handle_;  // Handle to the ALSA PCM recording device.
   snd_mixer_t* mixer_handle_; // Handle to the ALSA microphone mixer.
   snd_mixer_elem_t* mixer_element_handle_; // Handle to the capture element.
-  base::WeakPtrFactory<AlsaPcmInputStream> weak_factory_;
   scoped_ptr<uint8[]> audio_buffer_;  // Buffer used for reading audio data.
   bool read_callback_behind_schedule_;
 
+  // NOTE: Weak pointers must be invalidated before all other member variables.
+  base::WeakPtrFactory<AlsaPcmInputStream> weak_factory_;
+
   DISALLOW_COPY_AND_ASSIGN(AlsaPcmInputStream);
 };
 
diff --git a/media/audio/alsa/alsa_output.cc b/media/audio/alsa/alsa_output.cc
index 308bedc..690d738 100644
--- a/media/audio/alsa/alsa_output.cc
+++ b/media/audio/alsa/alsa_output.cc
@@ -153,11 +153,11 @@ AlsaPcmOutputStream::AlsaPcmOutputStream(const std::string& device_name,
       message_loop_(base::MessageLoop::current()),
       playback_handle_(NULL),
       frames_per_packet_(packet_size_ / bytes_per_frame_),
-      weak_factory_(this),
       state_(kCreated),
       volume_(1.0f),
       source_callback_(NULL),
-      audio_bus_(AudioBus::Create(params)) {
+      audio_bus_(AudioBus::Create(params)),
+      weak_factory_(this) {
   DCHECK(manager_->GetTaskRunner()->BelongsToCurrentThread());
   DCHECK_EQ(audio_bus_->frames() * bytes_per_frame_, packet_size_);
 
diff --git a/media/audio/alsa/alsa_output.h b/media/audio/alsa/alsa_output.h
index 65a23f7..1805645 100644
--- a/media/audio/alsa/alsa_output.h
+++ b/media/audio/alsa/alsa_output.h
@@ -201,10 +201,6 @@ class MEDIA_EXPORT AlsaPcmOutputStream : public AudioOutputStream {
   scoped_ptr<media::SeekableBuffer> buffer_;
   uint32 frames_per_packet_;
 
-  // Allows us to run tasks on the AlsaPcmOutputStream instance which are
-  // bound by its lifetime.
-  base::WeakPtrFactory<AlsaPcmOutputStream> weak_factory_;
-
   InternalState state_;
   float volume_;  // Volume level from 0.0 to 1.0.
 
@@ -217,6 +213,11 @@ class MEDIA_EXPORT AlsaPcmOutputStream : public AudioOutputStream {
   scoped_ptr<ChannelMixer> channel_mixer_;
   scoped_ptr<AudioBus> mixed_audio_bus_;
 
+  // Allows us to run tasks on the AlsaPcmOutputStream instance which are
+  // bound by its lifetime.
+  // NOTE: Weak pointers must be invalidated before all other member variables.
+  base::WeakPtrFactory<AlsaPcmOutputStream> weak_factory_;
+
   DISALLOW_COPY_AND_ASSIGN(AlsaPcmOutputStream);
 };