Added suspend/resume detection to the GpuWatchdogThread

content/gpu/gpu_watchdog_thread.cc

Index: content/gpu/gpu_watchdog_thread.cc
diff --git a/content/gpu/gpu_watchdog_thread.cc b/content/gpu/gpu_watchdog_thread.cc
index e823eddabb99215e949d9e6ea9264c2d811edf5f..ed9828287fe1bc56c625b852211c6ea70316f8ec 100644
--- a/content/gpu/gpu_watchdog_thread.cc
+++ b/content/gpu/gpu_watchdog_thread.cc
@@ -12,6 +12,7 @@
 #include "base/bind_helpers.h"
 #include "base/command_line.h"
 #include "base/compiler_specific.h"
+#include "base/power_monitor/power_monitor.h"
 #include "base/process/process.h"
 #include "build/build_config.h"
 #include "content/public/common/content_switches.h"
@@ -32,7 +33,8 @@ GpuWatchdogThread::GpuWatchdogThread(int timeout)
       arm_cpu_time_(),
 #endif
       task_observer_(this),
-      weak_factory_(this) {
+      weak_factory_(this),
+      suspended_(false) {
   DCHECK(timeout >= 0);
 
 #if defined(OS_WIN)
@@ -104,6 +106,10 @@ GpuWatchdogThread::~GpuWatchdogThread() {
   CloseHandle(watched_thread_handle_);
 #endif
 
+  base::PowerMonitor* power_monitor = base::PowerMonitor::Get();
+  if (power_monitor)
+    power_monitor->RemoveObserver(this);
+
   watched_message_loop_->RemoveTaskObserver(&task_observer_);
 }
 
@@ -132,7 +138,9 @@ void GpuWatchdogThread::OnAcknowledge() {
 }
 
 void GpuWatchdogThread::OnCheck(bool after_suspend) {
-  if (armed_)
+  // Do not create any new termination tasks if one has already been created
+  // or the system is suspended.
+  if (armed_ || suspended_)
     return;
 
   // Must set armed before posting the task. This task might be the only task
@@ -168,6 +176,9 @@ void GpuWatchdogThread::OnCheck(bool after_suspend) {
 
 // Use the --disable-gpu-watchdog command line switch to disable this.
 void GpuWatchdogThread::DeliberatelyTerminateToRecoverFromHang() {
+  // Should not get here while system is suspended

[Ken Russell (switch to Gerrit), 2013/08/05 22:08:01]

Please complete the sentence: "while the system is suspended.".

+  DCHECK(!suspended_);
+
 #if defined(OS_WIN)
   // Defer termination until a certain amount of CPU time has elapsed on the
   // watched thread.
@@ -214,6 +225,34 @@ void GpuWatchdogThread::DeliberatelyTerminateToRecoverFromHang() {
   terminated = true;
 }
 
+void GpuWatchdogThread::AddPowerObserver() {
+  message_loop()->PostTask(
+      FROM_HERE,
+      base::Bind(&GpuWatchdogThread::OnAddPowerObserver, this));
+}
+
+void GpuWatchdogThread::OnAddPowerObserver() {
+  base::PowerMonitor* power_monitor = base::PowerMonitor::Get();
+  DCHECK(power_monitor);
+  power_monitor->AddObserver(this);
+}
+
+void GpuWatchdogThread::OnSuspend() {
+  suspended_ = true;
+
+  // When suspending force an acknowledgement to cancel any pending termination
+  // tasks.
+  OnAcknowledge();

[Ken Russell (switch to Gerrit), 2013/08/05 22:08:01]

Is this correct and sufficient? The situation I'm concerned about is:

 - OnSuspend is called
 - It calls OnAcknowledge
 - That posts a delayed OnCheck message to its message loop (with
was_suspended=false)
 - The machine actually suspends
 - The machine wakes up
 - OnResume is called; suspended_=false
 - The previously posted delayed task is run

Will this work correctly?

Also, a DCHECK should be added to OnAcknowledge that it's being called on the
expected thread.

+}
+
+void GpuWatchdogThread::OnResume() {
+  suspended_ = false;
+
+  // After resuming jump-start the watchdog again
+  armed_ = false;
+  OnCheck(true);

[Ken Russell (switch to Gerrit), 2013/08/05 22:08:01]

Similarly for OnCheck. Per discussion with apatrick, perhaps make it a CHECK
rather than a DCHECK since the watchdog's disabled in debug builds.

+}
+
 #if defined(OS_WIN)
 base::TimeDelta GpuWatchdogThread::GetWatchedThreadTime() {
   FILETIME creation_time;