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}

2 files changed, 4 insertions, 6 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);
 };