Add a signal to the scheduler that a navigation is expected

components/scheduler/renderer/renderer_scheduler_impl.h

 // 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.
 
 #ifndef COMPONENTS_SCHEDULER_RENDERER_RENDERER_SCHEDULER_IMPL_H_
 #define COMPONENTS_SCHEDULER_RENDERER_RENDERER_SCHEDULER_IMPL_H_
 
 #include "base/atomicops.h"
 #include "base/synchronization/lock.h"
 #include "components/scheduler/child/idle_helper.h"
@@ skipping 32 matching lines @@
   void DidHandleInputEventOnCompositorThread(
       const blink::WebInputEvent& web_input_event,
       InputEventState event_state) override;
   void DidHandleInputEventOnMainThread(
       const blink::WebInputEvent& web_input_event) override;
   void DidAnimateForInputOnCompositorThread() override;
   void OnRendererHidden() override;
   void OnRendererVisible() override;
   void OnRendererBackgrounded() override;
   void OnRendererForegrounded() override;
-  void OnPageLoadStarted() override;
+  void OnNavigationExpected() override;
+  void OnNavigationCanceled() override;
+  void OnNavigationStarted() override;
   bool IsHighPriorityWorkAnticipated() override;
   bool ShouldYieldForHighPriorityWork() override;
   bool CanExceedIdleDeadlineIfRequired() const override;
   void AddTaskObserver(base::MessageLoop::TaskObserver* task_observer) override;
   void RemoveTaskObserver(
       base::MessageLoop::TaskObserver* task_observer) override;
   void Shutdown() override;
   void SuspendTimerQueue() override;
   void ResumeTimerQueue() override;
   void SetTimerQueueSuspensionWhenBackgroundedEnabled(bool enabled) override;
@@ skipping 62 matching lines @@
       const blink::WebInputEvent& web_input_event);
 
   // The amount of time which idle periods can continue being scheduled when the
   // renderer has been hidden, before going to sleep for good.
   static const int kEndIdleWhenHiddenDelayMillis = 10000;
 
   // The amount of time for which loading tasks will be prioritized over
   // other tasks during the initial page load.
   static const int kRailsInitialLoadingPrioritizationMillis = 1000;
 
+  // The maximum amount of time to wait for a OnNavigationStarted after a
+  // OnPageLoadExpected.

[Sami, 2015/09/24 14:15:04]

s/PageLoad/Navigation/ (in the variable name too)

[alex clarke (OOO till 29th), 2015/09/24 14:53:10]

I don't need this constant anymore.

+  static const int kMaxPageLoadExpectedWaitMillis = 2000;
+
   // For the purposes of deciding whether or not it's safe to turn timers and
   // loading tasks on only in idle periods, we regard the system as being as
   // being "idle period" starved if there hasn't been an idle period in the last
   // 10 seconds. This was chosen to be long enough to cover most anticipated
   // user gestures.
   static const int kIdlePeriodStarvationThresholdMillis = 10000;
 
   // The amount of time to wait before suspending shared timers after the
   // renderer has been backgrounded. This is used only if background suspension
   // of shared timers is enabled.
@@ skipping 94 matching lines @@
     bool touchstart_expected_soon;
     bool have_seen_a_begin_main_frame;
   };
 
   struct AnyThread {
     AnyThread();
 
     base::TimeTicks last_idle_period_end_time;
     base::TimeTicks rails_loading_priority_deadline;
     UserModel user_model;
+    bool navigation_expected;

[Sami, 2015/09/24 14:15:04]

Should this on the main thread struct instead? I think we're a bit inconsistent
about which thread owns which state, but navigation feels like it should be a
main thread only thing.

[alex clarke (OOO till 29th), 2015/09/24 14:53:10]

Done.

     bool awaiting_touch_start_response;
     bool in_idle_period;
     bool begin_main_frame_on_critical_path;
   };
 
   struct CompositorThreadOnly {
     CompositorThreadOnly();
     ~CompositorThreadOnly();
 
     blink::WebInputEvent::Type last_input_type;
@@ skipping 42 matching lines @@
 
   PollableThreadSafeFlag policy_may_need_update_;
   base::WeakPtrFactory<RendererSchedulerImpl> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(RendererSchedulerImpl);
 };
 
 }  // namespace scheduler
 
 #endif  // COMPONENTS_SCHEDULER_RENDERER_RENDERER_SCHEDULER_IMPL_H_