Hotlist Slow: Adopt ChromeOS Session restore tab loading timeouts.

chrome/browser/sessions/tab_loader_delegate.cc

 // Copyright 2014 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/sessions/tab_loader_delegate.h"
 
-#if !defined(OS_CHROMEOS)
+#include "net/base/network_change_notifier.h"
 
 namespace {
 
 // The timeout time after which the next tab gets loaded if the previous tab did
-// not finish loading yet.
-static const int kInitialDelayTimerMS = 100;
+// not finish loading yet. The used value is half of the median value of all
+// ChromeOS devices loading the 25 most common web pages. Half is chosen since
+// the loading time is a mix of server response and data bandwidth.
+static const int kInitialDelayTimerMS = 1500;
 
-class TabLoaderDelegateImpl : public TabLoaderDelegate {
+class TabLoaderDelegateImpl
+    : public TabLoaderDelegate,
+      public net::NetworkChangeNotifier::ConnectionTypeObserver {
  public:
-  TabLoaderDelegateImpl() {}
-  ~TabLoaderDelegateImpl() override {}
+  explicit TabLoaderDelegateImpl(TabLoaderCallback* callback);
+  ~TabLoaderDelegateImpl() override;
 
   // TabLoaderDelegate:
   base::TimeDelta GetTimeoutBeforeLoadingNextTab() const override {
     return base::TimeDelta::FromMilliseconds(kInitialDelayTimerMS);
   }
 
+  // net::NetworkChangeNotifier::ConnectionTypeObserver:
+  void OnConnectionTypeChanged(
+      net::NetworkChangeNotifier::ConnectionType type) override;
+
  private:
+  // The function to call when the connection type changes.
+  TabLoaderCallback* callback_;
+
   DISALLOW_COPY_AND_ASSIGN(TabLoaderDelegateImpl);
 };
+
+TabLoaderDelegateImpl::TabLoaderDelegateImpl(TabLoaderCallback* callback)
+    : callback_(callback) {
+  net::NetworkChangeNotifier::AddConnectionTypeObserver(this);
+  if (net::NetworkChangeNotifier::IsOffline()) {
+    // When we are off-line we do not allow loading of tabs, since each of
+    // these tabs would start loading simultaneously when going online.
+    // TODO(skuhne): Once we get a higher level resource control logic which
+    // distributes network access, we can remove this.
+    callback->SetTabLoadingEnabled(false);
+  }
+}
+
+TabLoaderDelegateImpl::~TabLoaderDelegateImpl() {
+  net::NetworkChangeNotifier::RemoveConnectionTypeObserver(this);
+}
+
+void TabLoaderDelegateImpl::OnConnectionTypeChanged(
+    net::NetworkChangeNotifier::ConnectionType type) {
+  callback_->SetTabLoadingEnabled(
+      type != net::NetworkChangeNotifier::CONNECTION_NONE);
+}
 }  // namespace
 
 // static
 scoped_ptr<TabLoaderDelegate> TabLoaderDelegate::Create(
     TabLoaderCallback* callback) {
-  return scoped_ptr<TabLoaderDelegate>(new TabLoaderDelegateImpl());
+  return scoped_ptr<TabLoaderDelegate>(
+      new TabLoaderDelegateImpl(callback));
 }
-
-#endif  // !defined(OS_CHROMEOS)