Adds a didReceiveInputEvent api to the blink scheduler

Source/platform/scheduler/Scheduler.cpp

 // 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.
 
 #include "config.h"
 #include "platform/scheduler/Scheduler.h"
 
 #include "platform/PlatformThreadData.h"
 #include "platform/Task.h"
 #include "platform/ThreadTimers.h"
@@ skipping 144 matching lines @@
 void Scheduler::postInputTask(const TraceLocation& location, const Task& task)
 {
     Locker<Mutex> lock(m_pendingTasksMutex);
     setLatencyMode(LowLatency);
     m_pendingHighPriorityTasks.append(TracedTask(task, location));
     atomicIncrement(&m_highPriorityTaskCount);
     maybePostMainThreadPendingHighPriorityTaskRunner();
     TRACE_COUNTER1(TRACE_DISABLED_BY_DEFAULT("blink.scheduler"), "PendingHighPriorityTasks", m_highPriorityTaskCount);
 }
 
+void Scheduler::didReceiveInputEvent()

[eseidel, 2014/09/10 16:10:34]

How often is this called?

[alexclarke, 2014/09/11 15:21:12]

At most a handful of times per frame.

+{
+    Locker<Mutex> lock(m_pendingTasksMutex);
+    setLatencyMode(LowLatency);
+}
+
 void Scheduler::postCompositorTask(const TraceLocation& location, const Task& task)
 {
     Locker<Mutex> lock(m_pendingTasksMutex);
     m_pendingHighPriorityTasks.append(TracedTask(task, location));
     atomicIncrement(&m_highPriorityTaskCount);
     maybePostMainThreadPendingHighPriorityTaskRunner();
     TRACE_COUNTER1(TRACE_DISABLED_BY_DEFAULT("blink.scheduler"), "PendingHighPriorityTasks", m_highPriorityTaskCount);
 }
 
 void Scheduler::maybePostMainThreadPendingHighPriorityTaskRunner()
@@ skipping 132 matching lines @@
 
 void Scheduler::TracedTask::run()
 {
     TRACE_EVENT2("blink", "TracedTask::run",
         "src_file", m_location.fileName(),
         "src_func", m_location.functionName());
     m_task();
 }
 
 } // namespace blink