Fix WeakPtrFactory ordering in media

A lot of these followed the pattern of listing WeakPtr last, which isn't
bad, but destructing WeakPtrFactory first invalidates *all* WeakPtrs it has
vended. And doing this consistently will allow us to turn on a Clang
checker (see the bug for more info).

BUG=303818
R=xhwang@chromium.org

Review URL: https://codereview.chromium.org/791633004

Cr-Commit-Position: refs/heads/master@{#307529}

9 files changed, 13 insertions, 19 deletions

diff --git a/media/blink/buffered_data_source.cc b/media/blink/buffered_data_source.cc
index be8d0f2..e3e12e0 100644
--- a/media/blink/buffered_data_source.cc
+++ b/media/blink/buffered_data_source.cc
@@ -104,8 +104,8 @@ BufferedDataSource::BufferedDataSource(
       media_log_(media_log),
       host_(host),
       downloading_cb_(downloading_cb),
-      weak_factory_(this),
-      weak_ptr_(weak_factory_.GetWeakPtr()) {
+      weak_factory_(this) {
+  weak_ptr_ = weak_factory_.GetWeakPtr();
   DCHECK(host_);
   DCHECK(!downloading_cb_.is_null());
   DCHECK(render_task_runner_->BelongsToCurrentThread());
diff --git a/media/blink/buffered_data_source.h b/media/blink/buffered_data_source.h
index 2179867..b047c19 100644
--- a/media/blink/buffered_data_source.h
+++ b/media/blink/buffered_data_source.h
@@ -232,13 +232,11 @@ class MEDIA_EXPORT BufferedDataSource : public DataSource {
 
   DownloadingCB downloading_cb_;
 
-  // NOTE: Weak pointers must be invalidated before all other member variables.
-  base::WeakPtrFactory<BufferedDataSource> weak_factory_;
-
   // Disallow rebinding WeakReference ownership to a different thread by keeping
   // a persistent reference. This avoids problems with the thread-safety of
   // reaching into this class from multiple threads to attain a WeakPtr.
-  const base::WeakPtr<BufferedDataSource> weak_ptr_;
+  base::WeakPtr<BufferedDataSource> weak_ptr_;
+  base::WeakPtrFactory<BufferedDataSource> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(BufferedDataSource);
 };
diff --git a/media/filters/decrypting_audio_decoder.h b/media/filters/decrypting_audio_decoder.h
index ddb89ac..8f6fc24 100644
--- a/media/filters/decrypting_audio_decoder.h
+++ b/media/filters/decrypting_audio_decoder.h
@@ -117,9 +117,8 @@ class MEDIA_EXPORT DecryptingAudioDecoder : public AudioDecoder {
 
   scoped_ptr<AudioTimestampHelper> timestamp_helper_;
 
-  // NOTE: Weak pointers must be invalidated before all other member variables.
-  base::WeakPtrFactory<DecryptingAudioDecoder> weak_factory_;
   base::WeakPtr<DecryptingAudioDecoder> weak_this_;
+  base::WeakPtrFactory<DecryptingAudioDecoder> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(DecryptingAudioDecoder);
 };
diff --git a/media/filters/decrypting_demuxer_stream.h b/media/filters/decrypting_demuxer_stream.h
index 4cf3f05..f66f9ab 100644
--- a/media/filters/decrypting_demuxer_stream.h
+++ b/media/filters/decrypting_demuxer_stream.h
@@ -125,9 +125,8 @@ class MEDIA_EXPORT DecryptingDemuxerStream : public DemuxerStream {
   // decrypting again in case the newly added key is the correct decryption key.
   bool key_added_while_decrypt_pending_;
 
-  // NOTE: Weak pointers must be invalidated before all other member variables.
-  base::WeakPtrFactory<DecryptingDemuxerStream> weak_factory_;
   base::WeakPtr<DecryptingDemuxerStream> weak_this_;
+  base::WeakPtrFactory<DecryptingDemuxerStream> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(DecryptingDemuxerStream);
 };
diff --git a/media/filters/decrypting_video_decoder.h b/media/filters/decrypting_video_decoder.h
index 9b57038..8e40502 100644
--- a/media/filters/decrypting_video_decoder.h
+++ b/media/filters/decrypting_video_decoder.h
@@ -110,9 +110,8 @@ class MEDIA_EXPORT DecryptingVideoDecoder : public VideoDecoder {
   // matching DecryptCB call (in DoDeliverFrame()).
   uint32 trace_id_;
 
-  // NOTE: Weak pointers must be invalidated before all other member variables.
-  base::WeakPtrFactory<DecryptingVideoDecoder> weak_factory_;
   base::WeakPtr<DecryptingVideoDecoder> weak_this_;
+  base::WeakPtrFactory<DecryptingVideoDecoder> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(DecryptingVideoDecoder);
 };
diff --git a/media/filters/renderer_impl.cc b/media/filters/renderer_impl.cc
index f9237da..e15ad6e 100644
--- a/media/filters/renderer_impl.cc
+++ b/media/filters/renderer_impl.cc
@@ -35,8 +35,8 @@ RendererImpl::RendererImpl(
       cdm_context_(nullptr),
       underflow_disabled_for_testing_(false),
       clockless_video_playback_enabled_for_testing_(false),
-      weak_factory_(this),
-      weak_this_(weak_factory_.GetWeakPtr()) {
+      weak_factory_(this) {
+  weak_this_ = weak_factory_.GetWeakPtr();
   DVLOG(1) << __FUNCTION__;
 }
 
diff --git a/media/filters/renderer_impl.h b/media/filters/renderer_impl.h
index 1000fa8..6a65bc0 100644
--- a/media/filters/renderer_impl.h
+++ b/media/filters/renderer_impl.h
@@ -171,9 +171,8 @@ class MEDIA_EXPORT RendererImpl : public Renderer {
   bool underflow_disabled_for_testing_;
   bool clockless_video_playback_enabled_for_testing_;
 
-  // NOTE: Weak pointers must be invalidated before all other member variables.
-  base::WeakPtrFactory<RendererImpl> weak_factory_;
   base::WeakPtr<RendererImpl> weak_this_;
+  base::WeakPtrFactory<RendererImpl> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(RendererImpl);
 };
diff --git a/media/mojo/services/mojo_renderer_service.cc b/media/mojo/services/mojo_renderer_service.cc
index 2c83a1e..4d120a8 100644
--- a/media/mojo/services/mojo_renderer_service.cc
+++ b/media/mojo/services/mojo_renderer_service.cc
@@ -41,8 +41,8 @@ static void MojoTrampoline(const mojo::Closure& closure) {
 MojoRendererService::MojoRendererService()
     : state_(STATE_UNINITIALIZED),
       last_media_time_usec_(0),
-      weak_factory_(this),
-      weak_this_(weak_factory_.GetWeakPtr()) {
+      weak_factory_(this) {
+  weak_this_ = weak_factory_.GetWeakPtr();
   DVLOG(1) << __FUNCTION__;
 
   scoped_refptr<base::SingleThreadTaskRunner> task_runner(
diff --git a/media/mojo/services/mojo_renderer_service.h b/media/mojo/services/mojo_renderer_service.h
index 71a4668..dc0183a 100644
--- a/media/mojo/services/mojo_renderer_service.h
+++ b/media/mojo/services/mojo_renderer_service.h
@@ -87,8 +87,8 @@ class MojoRendererService : public mojo::InterfaceImpl<mojo::MediaRenderer> {
   base::RepeatingTimer<MojoRendererService> time_update_timer_;
   uint64_t last_media_time_usec_;
 
-  base::WeakPtrFactory<MojoRendererService> weak_factory_;
   base::WeakPtr<MojoRendererService> weak_this_;
+  base::WeakPtrFactory<MojoRendererService> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(MojoRendererService);
 };