ozone: evdev: Add a couple more trace events

ui/events/ozone/evdev/tablet_event_converter_evdev.cc

 // 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 "ui/events/ozone/evdev/tablet_event_converter_evdev.h"
 
 #include <errno.h>
 #include <linux/input.h>
 
 #include "base/message_loop/message_loop.h"
+#include "base/trace_event/trace_event.h"
 #include "ui/events/event.h"
 #include "ui/events/ozone/evdev/device_event_dispatcher_evdev.h"
 
 namespace ui {
 
 TabletEventConverterEvdev::TabletEventConverterEvdev(
     int fd,
     base::FilePath path,
     int id,
     InputDeviceType type,
@@ skipping 16 matching lines @@
   y_abs_min_ = info.GetAbsMinimum(ABS_Y);
   y_abs_range_ = info.GetAbsMaximum(ABS_Y) - y_abs_min_ + 1;
 }
 
 TabletEventConverterEvdev::~TabletEventConverterEvdev() {
   Stop();
   close(fd_);
 }
 
 void TabletEventConverterEvdev::OnFileCanReadWithoutBlocking(int fd) {
+  TRACE_EVENT1("evdev",
+               "TabletEventConverterEvdev::OnFileCanReadWithoutBlocking", "fd",
+               fd);
+
   input_event inputs[4];
   ssize_t read_size = read(fd, inputs, sizeof(inputs));
   if (read_size < 0) {
     if (errno == EINTR || errno == EAGAIN)
       return;
     if (errno != ENODEV)
       PLOG(ERROR) << "error reading device " << path_.value();
     Stop();
     return;
   }
@@ skipping 114 matching lines @@
   UpdateCursor();
 
   dispatcher_->DispatchMouseMoveEvent(
       MouseMoveEventParams(input_device_.id, cursor_->GetLocation(),
                            TimeDeltaFromInputEvent(input)));
 
   abs_value_dirty_ = false;
 }
 
 }  // namespace ui