Convert MediaLog from being ref counted to owned by WebMediaPlayer.

content/renderer/media/render_media_log.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 "content/renderer/media/render_media_log.h"
 
 #include <sstream>
 
 #include "base/bind.h"
 #include "base/location.h"
@@ skipping 29 matching lines @@
 
 }  // namespace
 
 namespace content {
 
 RenderMediaLog::RenderMediaLog(const GURL& security_origin)
     : security_origin_(security_origin),
       task_runner_(base::ThreadTaskRunnerHandle::Get()),
       tick_clock_(new base::DefaultTickClock()),
       last_ipc_send_time_(tick_clock_->NowTicks()),
-      ipc_send_pending_(false) {
+      ipc_send_pending_(false),
+      weak_factory_(this) {
   DCHECK(RenderThread::Get())
       << "RenderMediaLog must be constructed on the render thread";
+  // Pre-bind the WeakPtr on the right thread since we'll receive calls from
+  // other threads and don't want races.
+  weak_this_ = weak_factory_.GetWeakPtr();
+}
+
+RenderMediaLog::~RenderMediaLog() {
+  DCHECK(task_runner_->BelongsToCurrentThread());
+
+  // There's no further chance to handle this, so send them now. This should not
+  // be racy since nothing should have a pointer to the media log on another
+  // thread by this point.
+  if (ipc_send_pending_)
+    SendQueuedMediaEvents();
 }
 
 void RenderMediaLog::AddEvent(std::unique_ptr<media::MediaLogEvent> event) {
   Log(event.get());
 
   // For enforcing delay until it's been a second since the last ipc message was
   // sent.
   base::TimeDelta delay_for_next_ipc_send;
 
   {
@@ skipping 34 matching lines @@
     if (ipc_send_pending_)
       return;
 
     ipc_send_pending_ = true;
     delay_for_next_ipc_send = base::TimeDelta::FromSeconds(1) -
                               (tick_clock_->NowTicks() - last_ipc_send_time_);
   }
 
   if (delay_for_next_ipc_send > base::TimeDelta()) {
     task_runner_->PostDelayedTask(
-        FROM_HERE, base::Bind(&RenderMediaLog::SendQueuedMediaEvents, this),
+        FROM_HERE,
+        base::Bind(&RenderMediaLog::SendQueuedMediaEvents, weak_this_),
         delay_for_next_ipc_send);
     return;
   }
 
   // It's been more than a second so send ASAP.
   if (task_runner_->BelongsToCurrentThread()) {
     SendQueuedMediaEvents();
     return;
   }
   task_runner_->PostTask(
-      FROM_HERE, base::Bind(&RenderMediaLog::SendQueuedMediaEvents, this));
+      FROM_HERE,
+      base::Bind(&RenderMediaLog::SendQueuedMediaEvents, weak_this_));
 }
 
 std::string RenderMediaLog::GetLastErrorMessage() {
   base::AutoLock auto_lock(lock_);
 
   // Return the conditional concatenation of the last pipeline error and the
   // last media error log.
   std::stringstream result;
   if (last_pipeline_error_) {
     result << MediaEventToLogString(*last_pipeline_error_)
            << (last_media_error_log_entry_ ? ", " : "");
   }
   if (last_media_error_log_entry_)
     result << MediaEventToLogString(*last_media_error_log_entry_);
   return result.str();
 }
 
 void RenderMediaLog::RecordRapporWithSecurityOrigin(const std::string& metric) {
   if (!task_runner_->BelongsToCurrentThread()) {
     task_runner_->PostTask(
         FROM_HERE, base::Bind(&RenderMediaLog::RecordRapporWithSecurityOrigin,
-                              this, metric));
+                              weak_this_, metric));
     return;
   }
 
   GetContentClient()->renderer()->RecordRapporURL(metric, security_origin_);
 }
 
 void RenderMediaLog::SendQueuedMediaEvents() {
   DCHECK(task_runner_->BelongsToCurrentThread());
 
   std::vector<media::MediaLogEvent> events_to_send;
@@ skipping 10 matching lines @@
 
     if (last_duration_changed_event_) {
       queued_media_events_.push_back(*last_duration_changed_event_);
       last_duration_changed_event_.reset();
     }
 
     queued_media_events_.swap(events_to_send);
     last_ipc_send_time_ = tick_clock_->NowTicks();
   }
 
+  if (events_to_send.empty())
+    return;
+
   RenderThread::Get()->Send(new ViewHostMsg_MediaLogEvents(events_to_send));
 }
 
-RenderMediaLog::~RenderMediaLog() {
-}
-
 void RenderMediaLog::SetTickClockForTesting(
     std::unique_ptr<base::TickClock> tick_clock) {
   base::AutoLock auto_lock(lock_);
   tick_clock_.swap(tick_clock);
   last_ipc_send_time_ = tick_clock_->NowTicks();
 }
 
 void RenderMediaLog::SetTaskRunnerForTesting(
     const scoped_refptr<base::SingleThreadTaskRunner>& task_runner) {
   task_runner_ = task_runner;
 }
 
 }  // namespace content