Add a signal to the scheduler that a navigation is expected

third_party/WebKit/Source/core/loader/NavigationScheduler.cpp

Index: third_party/WebKit/Source/core/loader/NavigationScheduler.cpp
diff --git a/third_party/WebKit/Source/core/loader/NavigationScheduler.cpp b/third_party/WebKit/Source/core/loader/NavigationScheduler.cpp
index 440e46d4a0cc6ddb51934009f6eb554f1f7b6d1e..4c2a61a75ea9e694b25d1b79548a5f582f414f6b 100644
--- a/third_party/WebKit/Source/core/loader/NavigationScheduler.cpp
+++ b/third_party/WebKit/Source/core/loader/NavigationScheduler.cpp
@@ -420,7 +420,9 @@ void NavigationScheduler::startTimer()
     if (!m_redirect->shouldStartTimer(m_frame))
         return;
 
-    Platform::current()->currentThread()->scheduler()->loadingTaskRunner()->postDelayedTask(
+    WebScheduler* scheduler = Platform::current()->currentThread()->scheduler();
+    scheduler->onNavigationExpected();
+    scheduler->loadingTaskRunner()->postDelayedTask(
         FROM_HERE, m_navigateTaskFactory->cancelAndCreate(), m_redirect->delay() * 1000.0);
 
     InspectorInstrumentation::frameScheduledNavigation(m_frame, m_redirect->delay());
@@ -428,8 +430,10 @@ void NavigationScheduler::startTimer()
 
 void NavigationScheduler::cancel()
 {
-    if (m_navigateTaskFactory->isPending())
+    if (m_navigateTaskFactory->isPending()) {
+        Platform::current()->currentThread()->scheduler()->onNavigationCanceled();
         InspectorInstrumentation::frameClearedScheduledNavigation(m_frame);
+    }
     m_navigateTaskFactory->cancel();
     m_redirect.clear();
 }