Disable scheduler deadline task on battery power in Windows

cc/scheduler/scheduler.cc

Index: cc/scheduler/scheduler.cc
diff --git a/cc/scheduler/scheduler.cc b/cc/scheduler/scheduler.cc
index 44d7d77ace95b2f839154854882e659ef51feda6..9c0c163306048a9e512cccc4a6b6b4edbfb3c736 100644
--- a/cc/scheduler/scheduler.cc
+++ b/cc/scheduler/scheduler.cc
@@ -9,6 +9,7 @@
 #include "base/debug/trace_event.h"
 #include "base/debug/trace_event_argument.h"
 #include "base/logging.h"
+#include "base/power_monitor/power_monitor.h"
 #include "base/single_thread_task_runner.h"
 #include "cc/debug/devtools_instrumentation.h"
 #include "cc/debug/traced_value.h"
@@ -117,9 +118,16 @@ Scheduler::Scheduler(
   background_frame_source_ =
       frame_sources_constructor->ConstructBackgroundFrameSource(this);
   frame_source_->AddSource(background_frame_source_);
+
+  if (settings_.prioritize_impl_latency_on_battery) {
+    SetupPowerMonitoring();
+  }
 }
 
 Scheduler::~Scheduler() {
+  if (settings_.prioritize_impl_latency_on_battery) {
+    TeardownPowerMonitoring();
+  }
 }
 
 base::TimeTicks Scheduler::Now() const {
@@ -131,6 +139,23 @@ base::TimeTicks Scheduler::Now() const {
   return now;
 }
 
+void Scheduler::SetupPowerMonitoring() {
+  base::PowerMonitor* power_monitor = base::PowerMonitor::Get();
+  DCHECK(power_monitor != NULL);
+  power_monitor->AddObserver(this);
+  on_battery_power_ = power_monitor->IsOnBatteryPower();
+}
+
+void Scheduler::TeardownPowerMonitoring() {
+  base::PowerMonitor* power_monitor = base::PowerMonitor::Get();
+  DCHECK(power_monitor != NULL);
+  power_monitor->RemoveObserver(this);
+}
+
+void Scheduler::OnPowerStateChange(bool on_battery_power) {
+  on_battery_power_ = on_battery_power;
+}
+
 void Scheduler::CommitVSyncParameters(base::TimeTicks timebase,
                                       base::TimeDelta interval) {
   // TODO(brianderson): We should not be receiving 0 intervals.
@@ -489,6 +514,7 @@ void Scheduler::BeginImplFrame(const BeginFrameArgs& args) {
   DCHECK_EQ(state_machine_.begin_impl_frame_state(),
             SchedulerStateMachine::BEGIN_IMPL_FRAME_STATE_IDLE);
   DCHECK(state_machine_.HasInitializedOutputSurface());
+  DCHECK(begin_impl_frame_deadline_task_.IsCancelled());
 
   advance_commit_state_task_.Cancel();
 
@@ -509,15 +535,22 @@ void Scheduler::BeginImplFrame(const BeginFrameArgs& args) {
   ProcessScheduledActions();
 
   state_machine_.OnBeginImplFrameDeadlinePending();
-  ScheduleBeginImplFrameDeadline(
-      AdjustedBeginImplFrameDeadline(args, draw_duration_estimate));
+
+  if (!settings_.using_synchronous_renderer_compositor) {
+    ScheduleBeginImplFrameDeadline(
+        AdjustedBeginImplFrameDeadline(args, draw_duration_estimate));
+  } else {
+    OnBeginImplFrameDeadline();
+  }
 }
 
 base::TimeTicks Scheduler::AdjustedBeginImplFrameDeadline(
     const BeginFrameArgs& args,
     base::TimeDelta draw_duration_estimate) const {
   if (settings_.using_synchronous_renderer_compositor) {
-    // The synchronous compositor needs to draw right away.
+    return base::TimeTicks();
+  } else if (settings_.prioritize_impl_latency_on_battery &&

[danakj, 2014/10/09 17:04:01]

just if (on_battery_power_) should be enough?

+             on_battery_power_) {
     return base::TimeTicks();
   } else if (state_machine_.ShouldTriggerBeginImplFrameDeadlineEarly()) {
     // We are ready to draw a new active tree immediately.
@@ -541,15 +574,6 @@ base::TimeTicks Scheduler::AdjustedBeginImplFrameDeadline(
 void Scheduler::ScheduleBeginImplFrameDeadline(base::TimeTicks deadline) {
   TRACE_EVENT1(
       "cc", "Scheduler::ScheduleBeginImplFrameDeadline", "deadline", deadline);
-  if (settings_.using_synchronous_renderer_compositor) {
-    // The synchronous renderer compositor has to make its GL calls
-    // within this call.
-    // TODO(brianderson): Have the OutputSurface initiate the deadline tasks
-    // so the sychronous renderer compositor can take advantage of splitting
-    // up the BeginImplFrame and deadline as well.
-    OnBeginImplFrameDeadline();
-    return;
-  }
   begin_impl_frame_deadline_task_.Cancel();
   begin_impl_frame_deadline_task_.Reset(begin_impl_frame_deadline_closure_);
 
@@ -701,6 +725,9 @@ void Scheduler::AsValueInto(base::debug::TracedValue* state) const {
                     !poll_for_draw_triggers_task_.IsCancelled());
   state->SetBoolean("advance_commit_state_task_",
                     !advance_commit_state_task_.IsCancelled());
+  if (settings_.prioritize_impl_latency_on_battery) {
+    state->SetBoolean("on_battery_power_", on_battery_power_);
+  }
   state->BeginDictionary("begin_impl_frame_args");
   begin_impl_frame_args_.AsValueInto(state);
   state->EndDictionary();