Remove calls to ObserverList::size() from PluginInstaller.

chrome/browser/plugins/plugin_installer.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 "chrome/browser/plugins/plugin_installer.h"
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
 #include "base/process/process.h"
 #include "base/strings/stringprintf.h"
@@ skipping 49 matching lines @@
   if (error != net::OK) {
     BrowserThread::PostTask(
         BrowserThread::UI, FROM_HERE,
         base::Bind(callback, static_cast<DownloadItem*>(NULL), error));
   }
 }
 
 }  // namespace
 
 PluginInstaller::PluginInstaller()
-    : state_(INSTALLER_STATE_IDLE) {
+    : state_(INSTALLER_STATE_IDLE),
+      strong_observer_count_(0) {
 }
 
 PluginInstaller::~PluginInstaller() {
 }
 
 void PluginInstaller::OnDownloadUpdated(DownloadItem* download) {
   DownloadItem::DownloadState state = download->GetState();
   switch (state) {
     case DownloadItem::IN_PROGRESS:
       return;
@@ skipping 21 matching lines @@
   download->RemoveObserver(this);
 }
 
 void PluginInstaller::OnDownloadDestroyed(DownloadItem* download) {
   DCHECK_EQ(INSTALLER_STATE_DOWNLOADING, state_);
   state_ = INSTALLER_STATE_IDLE;
   download->RemoveObserver(this);
 }
 
 void PluginInstaller::AddObserver(PluginInstallerObserver* observer) {
+  strong_observer_count_++;
   observers_.AddObserver(observer);
 }
 
 void PluginInstaller::RemoveObserver(PluginInstallerObserver* observer) {
+  strong_observer_count_--;
   observers_.RemoveObserver(observer);
-  if (observers_.size() == weak_observers_.size()) {
+  if (strong_observer_count_ == 0) {
     FOR_EACH_OBSERVER(WeakPluginInstallerObserver, weak_observers_,
                       OnlyWeakObserversLeft());
   }
 }
 
 void PluginInstaller::AddWeakObserver(WeakPluginInstallerObserver* observer) {
   weak_observers_.AddObserver(observer);
 }
 
 void PluginInstaller::RemoveWeakObserver(
@@ skipping 49 matching lines @@
   DCHECK_EQ(INSTALLER_STATE_DOWNLOADING, state_);
   state_ = INSTALLER_STATE_IDLE;
   FOR_EACH_OBSERVER(PluginInstallerObserver, observers_, DownloadError(msg));
 }
 
 void PluginInstaller::DownloadCancelled() {
   DCHECK_EQ(INSTALLER_STATE_DOWNLOADING, state_);
   state_ = INSTALLER_STATE_IDLE;
   FOR_EACH_OBSERVER(PluginInstallerObserver, observers_, DownloadCancelled());
 }