Prevent hang monitor restarts when hidden

content/browser/renderer_host/render_widget_host_unittest.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 "base/basictypes.h"
 #include "base/bind.h"
 #include "base/command_line.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/memory/shared_memory.h"
 #include "base/timer/timer.h"
@@ skipping 974 matching lines @@
 
   // Wait long enough for the second timeout and see if it fired.
   base::MessageLoop::current()->PostDelayedTask(
       FROM_HERE,
       base::MessageLoop::QuitClosure(),
       TimeDelta::FromMilliseconds(25));
   base::MessageLoop::current()->Run();
   EXPECT_TRUE(host_->unresponsive_timer_fired());
 }
 
+// Test that the hang monitor timer is effectively disabled when the widget is
+// hidden.
+TEST_F(RenderWidgetHostTest, HangMonitorTimeoutDisabledWhenHidden) {
+  host_->StartHangMonitorTimeout(TimeDelta::FromMicroseconds(1));
+
+  // Hiding the widget should deactivate the timeout.
+  host_->WasHidden();
+
+  // The timeout should not fire.
+  EXPECT_FALSE(host_->unresponsive_timer_fired());
+  base::MessageLoop::current()->PostDelayedTask(
+      FROM_HERE,
+      base::MessageLoop::QuitClosure(),
+      TimeDelta::FromMicroseconds(2));
+  base::MessageLoop::current()->Run();
+  EXPECT_FALSE(host_->unresponsive_timer_fired());
+
+  // The timeout should never reactivate while hidden.
+  host_->StartHangMonitorTimeout(TimeDelta::FromMicroseconds(1));
+  base::MessageLoop::current()->PostDelayedTask(
+      FROM_HERE,
+      base::MessageLoop::QuitClosure(),
+      TimeDelta::FromMicroseconds(2));
+  base::MessageLoop::current()->Run();
+  EXPECT_FALSE(host_->unresponsive_timer_fired());
+
+  // Showing the widget should restore normal timeout behavior.
+  host_->WasShown(ui::LatencyInfo());
+  host_->StartHangMonitorTimeout(TimeDelta::FromMicroseconds(1));
+  base::MessageLoop::current()->PostDelayedTask(
+      FROM_HERE,
+      base::MessageLoop::QuitClosure(),
+      TimeDelta::FromMicroseconds(2));
+  base::MessageLoop::current()->Run();
+  EXPECT_TRUE(host_->unresponsive_timer_fired());
+}
+
 // Test that the hang monitor catches two input events but only one ack.
 // This can happen if the second input event causes the renderer to hang.
 // This test will catch a regression of crbug.com/111185.
 TEST_F(RenderWidgetHostTest, MultipleInputEvents) {
   // Configure the host to wait 10ms before considering
   // the renderer hung.
   host_->set_hung_renderer_delay_ms(10);
 
   // Send two events but only one ack.
   SimulateKeyboardEvent(WebInputEvent::RawKeyDown);
@@ skipping 464 matching lines @@
   // Having an initial size set means that the size information had been sent
   // with the reqiest to new up the RenderView and so subsequent WasResized
   // calls should not result in new IPC (unless the size has actually changed).
   host_->WasResized();
   EXPECT_FALSE(process_->sink().GetUniqueMessageMatching(ViewMsg_Resize::ID));
   EXPECT_EQ(initial_size_, host_->old_resize_params_->new_size);
   EXPECT_TRUE(host_->resize_ack_pending_);
 }
 
 }  // namespace content