scheduler: Add support for tracing scheduler state

content/renderer/scheduler/renderer_scheduler_impl.h

Index: content/renderer/scheduler/renderer_scheduler_impl.h
diff --git a/content/renderer/scheduler/renderer_scheduler_impl.h b/content/renderer/scheduler/renderer_scheduler_impl.h
index 555573d19f3a4dc0cada0bc4f2cdc8764065ad34..72a7ce7c794a0ef575d5e78c48b5e04dcd8aa114 100644
--- a/content/renderer/scheduler/renderer_scheduler_impl.h
+++ b/content/renderer/scheduler/renderer_scheduler_impl.h
@@ -12,6 +12,12 @@
 #include "content/renderer/scheduler/single_thread_idle_task_runner.h"
 #include "content/renderer/scheduler/task_queue_manager.h"
 
+namespace base {
+namespace debug {
+class ConvertableToTraceFormat;
+}
+}
+
 namespace content {
 
 class RendererSchedulerSelector;
@@ -76,6 +82,11 @@ class RendererSchedulerImpl : public RendererScheduler,
     kCompositorPriorityPolicy,
   };
 
+  // Returns the serialized scheduler state for tracing.
+  scoped_refptr<base::debug::ConvertableToTraceFormat> AsValueLocked() const;
+  static const char* TaskQueueIdToString(QueueId queue_id);
+  static const char* PolicyToString(Policy policy);
+
   // The time we should stay in CompositorPriority mode for after a touch event.
   static const int kCompositorPriorityAfterTouchMillis = 100;
 
@@ -111,7 +122,7 @@ class RendererSchedulerImpl : public RendererScheduler,
 
   // The incoming_signals_lock_ mutex protects access to last_input_time_
   // and write access to policy_may_need_update_.
-  base::Lock incoming_signals_lock_;
+  mutable base::Lock incoming_signals_lock_;

[alexclarke, 2014/10/27 17:58:11]

Hmm I thought that AssertAcquired was const:

https://code.google.com/p/chromium/codesearch#chromium/src/base/synchronizati...

[Sami, 2014/10/28 12:57:47]

Oops, I added this since I was taking the lock earlier but don't need to do that
anymore => removed.

   base::TimeTicks last_input_time_;
 
   base::WeakPtr<RendererSchedulerImpl> weak_renderer_scheduler_ptr_;