ozone: evdev: Fix possibility of stuck mouse buttons

ui/events/ozone/evdev/libgestures_glue/gesture_interpreter_libevdev_cros.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/libgestures_glue/gesture_interpreter_libevdev_cros.h"
 
 #include <gestures/gestures.h>
 #include <libevdev/libevdev.h>
 #include <linux/input.h>
 
@@ skipping 190 matching lines @@
     hwstate.buttons_down |= GESTURES_BUTTON_MIDDLE;
   if (Event_Get_Button_Right(evdev))
     hwstate.buttons_down |= GESTURES_BUTTON_RIGHT;
 
   GestureInterpreterPushHardwareState(interpreter_, &hwstate);
 }
 
 void GestureInterpreterLibevdevCros::OnLibEvdevCrosStopped(
     Evdev* evdev,
     EventStateRec* state) {
-  ReleaseKeys();
+  stime_t timestamp = StimeNow();
+
+  ReleaseKeys(timestamp);
+  ReleaseMouseButtons(timestamp);
 }
 
 void GestureInterpreterLibevdevCros::SetAllowedKeys(
     scoped_ptr<std::set<DomCode>> allowed_keys) {
   if (!allowed_keys) {
     allowed_keys_.reset();
     return;
   }
 
   allowed_keys_.reset(new std::set<int>());
@@ skipping 190 matching lines @@
   DVLOG(3) << base::StringPrintf("Gesture Metrics: [%f, %f] type=%d",
                                  metrics->data[0],
                                  metrics->data[1],
                                  metrics->type);
   NOTIMPLEMENTED();
 }
 
 void GestureInterpreterLibevdevCros::DispatchMouseButton(unsigned int button,
                                                          bool down,
                                                          stime_t time) {
+  if (!SetMouseButtonState(button, down))
+    return;  // No change.
+
   bool allow_remap = is_mouse_;
   dispatcher_->DispatchMouseButtonEvent(
       MouseButtonEventParams(id_, cursor_->GetLocation(), button, down,
                              allow_remap, StimeToTimedelta(time)));
 }
 
 void GestureInterpreterLibevdevCros::DispatchChangedKeys(
     unsigned long* new_key_state,
     stime_t timestamp) {
   unsigned long key_state_diff[EVDEV_BITS_TO_LONGS(KEY_CNT)];
@@ skipping 22 matching lines @@
       dispatcher_->DispatchKeyEvent(
           KeyEventParams(id_, key, value, StimeToTimedelta(timestamp)));
     }
   }
 
   // Update internal key state.
   for (unsigned long i = 0; i < EVDEV_BITS_TO_LONGS(KEY_CNT); ++i)
     prev_key_state_[i] = new_key_state[i];
 }
 
-void GestureInterpreterLibevdevCros::ReleaseKeys() {
+void GestureInterpreterLibevdevCros::ReleaseKeys(stime_t timestamp) {
   unsigned long new_key_state[EVDEV_BITS_TO_LONGS(KEY_CNT)];
   memset(&new_key_state, 0, sizeof(new_key_state));
 
-  DispatchChangedKeys(new_key_state, StimeNow());
+  DispatchChangedKeys(new_key_state, timestamp);
+}
+
+bool GestureInterpreterLibevdevCros::SetMouseButtonState(unsigned int button,
+                                                         bool down) {
+  DCHECK(BTN_MOUSE <= button && button < BTN_JOYSTICK);
+  int button_offset = button - BTN_MOUSE;
+
+  if (mouse_button_state_.test(button_offset) == down)
+    return false;
+
+  // State transition: !(down) -> (down)
+  if (down)
+    mouse_button_state_.set(button_offset);
+  else
+    mouse_button_state_.reset(button_offset);
+
+  return true;
+}
+
+void GestureInterpreterLibevdevCros::ReleaseMouseButtons(stime_t timestamp) {
+  DispatchMouseButton(BTN_LEFT, false /* down */, timestamp);
+  DispatchMouseButton(BTN_MIDDLE, false /* down */, timestamp);
+  DispatchMouseButton(BTN_RIGHT, false /* down */, timestamp);
 }
 
 }  // namespace ui