ResourceScheduler should use renderer notifications instead of MRUCache to track renderers.

content/browser/loader/render_view_host_tracker.cc

+// Copyright (c) 2013 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/browser/loader/render_view_host_tracker.h"
+
+#include "base/bind_helpers.h"
+#include "base/stl_util.h"
+#include "content/browser/loader/resource_dispatcher_host_impl.h"
+#include "content/browser/loader/resource_scheduler.h"
+#include "content/public/browser/browser_thread.h"
+#include "content/public/browser/notification_service.h"
+#include "content/public/browser/notification_types.h"
+#include "content/public/browser/render_process_host.h"
+#include "content/public/browser/render_view_host.h"
+
+namespace content {
+
+RenderViewHostTracker::RenderViewHostTracker() {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+  registrar_.Add(this, NOTIFICATION_RENDER_VIEW_HOST_CREATED,
+                 NotificationService::AllSources());
+}
+
+RenderViewHostTracker::~RenderViewHostTracker() {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+  DCHECK(observers_.empty());
+}
+
+void RenderViewHostTracker::Observe(
+    int type,
+    const NotificationSource& source,
+    const NotificationDetails& details) {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+  RenderViewHost* rvh = content::Source<RenderViewHost>(source).ptr();
+  int child_id = rvh->GetProcess()->GetID();
+  int route_id = rvh->GetRoutingID();
+
+  switch (type) {
+    case NOTIFICATION_RENDER_VIEW_HOST_CREATED:
+      Observer* observer = new Observer(rvh, this);
+      observers_.insert(observer);
+      BrowserThread::PostTask(
+          BrowserThread::IO, FROM_HERE,
+          base::Bind(&ResourceDispatcherHostImpl::OnRenderViewHostCreated,
+                     base::Unretained(ResourceDispatcherHostImpl::Get()),
+                     child_id, route_id));
+      break;
+  }
+}
+
+void RenderViewHostTracker::RemoveObserver(Observer* observer) {
+  DCHECK(ContainsKey(observers_, observer));
+  observers_.erase(observer);
+  delete observer;
+}
+
+RenderViewHostTracker::Observer::Observer(RenderViewHost* rvh,
+                                          RenderViewHostTracker* tracker)
+    : RenderViewHostObserver(rvh),
+      tracker_(tracker) {
+}
+
+RenderViewHostTracker::Observer::~Observer() {
+}
+
+void RenderViewHostTracker::Observer::RenderViewHostDestroyed(
+    RenderViewHost* rvh) {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+  int child_id = rvh->GetProcess()->GetID();
+  int route_id = rvh->GetRoutingID();
+
+  BrowserThread::PostTask(
+      BrowserThread::IO, FROM_HERE,
+      base::Bind(&ResourceDispatcherHostImpl::OnRenderViewHostDeleted,
+                 base::Unretained(ResourceDispatcherHostImpl::Get()),
+                 child_id, route_id));
+
+  tracker_->RemoveObserver(this);
+}
+
+}  // namespace content