evdev: Fix infinite loop when devices are unplugged

ui/events/ozone/evdev/event_converter.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/event_converter.h"
 
 #include <errno.h>
 #include <linux/input.h>
 
 #include "ui/events/ozone/evdev/event_modifiers.h"
 
 namespace ui {
 
 // Number of events to read at a time.
 const int kEvdevBufferSize = 64;
 
 EventConverterEvdev::EventConverterEvdev(int fd,
                                          base::FilePath path,
                                          EventModifiersEvdev* modifiers)
     : fd_(fd), path_(path), modifiers_(modifiers) {}
 
-EventConverterEvdev::~EventConverterEvdev() { close(fd_); }
+EventConverterEvdev::~EventConverterEvdev() {
+  Stop();
+  close(fd_);
+}
+
+void EventConverterEvdev::Start() {
+  base::MessagePumpOzone::Current()->WatchFileDescriptor(
+      fd_, true, base::MessagePumpLibevent::WATCH_READ, &controller_, this);
+}
+
+void EventConverterEvdev::Stop() { controller_.StopWatchingFileDescriptor(); }
 
 void EventConverterEvdev::OnFileCanReadWithoutBlocking(int fd) {
   input_event inputs[kEvdevBufferSize];
   ssize_t read_size = read(fd, inputs, sizeof(inputs));
   if (read_size <= 0) {
     if (errno == EINTR || errno == EAGAIN)
       return;
     PLOG(ERROR) << "error reading device " << path_.value();
+    Stop();
     return;
   }
 
   CHECK_EQ(read_size % sizeof(*inputs), 0u);
   ProcessEvents(inputs, read_size / sizeof(*inputs));
 }
 
 void EventConverterEvdev::OnFileCanWriteWithoutBlocking(int fd) {
   NOTREACHED();
 }
 
 }  // namespace ui