Make Callback::Reset() return a copy to support use-cases where Run() ends up modifying |*this|.

media/filters/video_renderer_base.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "base/bind.h"
 #include "base/callback.h"
+#include "base/callback_helpers.h"
 #include "base/threading/platform_thread.h"
 #include "media/base/buffers.h"
 #include "media/base/filter_host.h"
 #include "media/base/limits.h"
 #include "media/base/pipeline.h"
 #include "media/base/video_frame.h"
 #include "media/filters/video_renderer_base.h"
 
 namespace media {
 
@@ skipping 348 matching lines @@
   }
 
   if (!frame) {
     if (state_ != kSeeking)
       return;
 
     // Abort seek early for a NULL frame because we won't get more frames.
     // A new seek will be requested after this one completes so there is no
     // point trying to collect more frames.
     state_ = kPrerolled;
-    ResetAndRunCB(&seek_cb_, PIPELINE_OK);
+    base::ResetAndReturn(&seek_cb_).Run(PIPELINE_OK);
     return;
   }
 
   // Discard frames until we reach our desired seek timestamp.
   if (state_ == kSeeking && !frame->IsEndOfStream() &&
       (frame->GetTimestamp() + frame->GetDuration()) <= seek_timestamp_) {
     AttemptRead_Locked();
     return;
   }
 
@@ skipping 38 matching lines @@
     // Because we might remain in the prerolled state for an undetermined amount
     // of time (i.e., we were not playing before we received a seek), we'll
     // manually update the current frame and notify the subclass below.
     if (!ready_frames_.front()->IsEndOfStream()) {
       current_frame_ = ready_frames_.front();
       ready_frames_.pop_front();
     }
 
     // ...and we're done seeking!
     DCHECK(!seek_cb_.is_null());
-    ResetAndRunCB(&seek_cb_, PIPELINE_OK);
+    base::ResetAndReturn(&seek_cb_).Run(PIPELINE_OK);
 
     base::AutoUnlock ul(lock_);
     paint_cb_.Run();
   }
 }
 
 void VideoRendererBase::AttemptRead_Locked() {
   lock_.AssertAcquired();
   DCHECK_NE(kEnded, state_);
 
@@ skipping 54 matching lines @@
 
 int VideoRendererBase::NumFrames_Locked() const {
   lock_.AssertAcquired();
   int outstanding_frames =
       (current_frame_ ? 1 : 0) + (last_available_frame_ ? 1 : 0) +
       (current_frame_ && (current_frame_ == last_available_frame_) ? -1 : 0);
   return ready_frames_.size() + outstanding_frames;
 }
 
 }  // namespace media