WeakPtr destruction order cleanup: media edition.

media/audio/alsa/alsa_input.h

Index: media/audio/alsa/alsa_input.h
diff --git a/media/audio/alsa/alsa_input.h b/media/audio/alsa/alsa_input.h
index 6e9aad9056ebf643d5f2b3c1b2ab6c51f3417d33..d0fc02ab0070da00fbce51b1d6d4b23a84012dea 100644
--- a/media/audio/alsa/alsa_input.h
+++ b/media/audio/alsa/alsa_input.h
@@ -80,10 +80,13 @@ 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: This must always be last so it's invalidated before other member
+  // variables might be accessed.
+  base::WeakPtrFactory<AlsaPcmInputStream> weak_factory_;
+
   DISALLOW_COPY_AND_ASSIGN(AlsaPcmInputStream);
 };