Corner Passthrough for Accessibility

ui/chromeos/touch_exploration_controller.cc

Index: ui/chromeos/touch_exploration_controller.cc
diff --git a/ui/chromeos/touch_exploration_controller.cc b/ui/chromeos/touch_exploration_controller.cc
index 0a63014062c19cbb9580426b5854b23c3a2008b7..1f5e50d329030a38ef9673cc4bfcd13372dfb0f0 100644
--- a/ui/chromeos/touch_exploration_controller.cc
+++ b/ui/chromeos/touch_exploration_controller.cc
@@ -23,6 +23,10 @@ namespace {
 // Delay between adjustment sounds.
 const base::TimeDelta kSoundDelay = base::TimeDelta::FromMilliseconds(150);
 
+// Delay before corner passthrough activates.
+const base::TimeDelta kCornerPassthroughDelay =
+    base::TimeDelta::FromMilliseconds(500);
+
 // In ChromeOS, VKEY_LWIN is synonymous for the search key.
 const ui::KeyboardCode kChromeOSSearchKey = ui::VKEY_LWIN;
 }  // namespace
@@ -36,7 +40,8 @@ TouchExplorationController::TouchExplorationController(
       event_handler_for_testing_(NULL),
       gesture_provider_(this),
       prev_state_(NO_FINGERS_DOWN),
-      VLOG_on_(true) {
+      VLOG_on_(true),
+      waiting_for_corner_passthrough_(false) {
   CHECK(root_window);
   root_window->GetHost()->GetEventSource()->AddEventRewriter(this);
 }
@@ -73,6 +78,13 @@ ui::EventRewriteStatus TouchExplorationController::RewriteEvent(
     // this event under this new state.
   }
 
+  if (long_press_timer_.IsRunning() &&
+      event.time_stamp() - initial_press_->time_stamp() >
+          gesture_detector_config_.longpress_timeout) {
+    long_press_timer_.Stop();
+    OnLongPressTimerFired();
+  }
+
   const ui::EventType type = touch_event.type();
   const gfx::PointF& location = touch_event.location_f();
   const int touch_id = touch_event.touch_id();
@@ -132,6 +144,8 @@ ui::EventRewriteStatus TouchExplorationController::RewriteEvent(
       return InTouchExploreSecondPress(touch_event, rewritten_event);
     case TWO_TO_ONE_FINGER:
       return InTwoToOneFinger(touch_event, rewritten_event);
+    case CORNER_PASSTHROUGH:
+      return InCornerPassthrough(touch_event, rewritten_event);
     case PASSTHROUGH:
       return InPassthrough(touch_event, rewritten_event);
     case WAIT_FOR_RELEASE:
@@ -152,29 +166,63 @@ ui::EventRewriteStatus TouchExplorationController::NextDispatchEvent(
 ui::EventRewriteStatus TouchExplorationController::InNoFingersDown(
     const ui::TouchEvent& event, scoped_ptr<ui::Event>* rewritten_event) {
   const ui::EventType type = event.type();
-  if (type == ui::ET_TOUCH_PRESSED) {
-    initial_press_.reset(new TouchEvent(event));
-    last_unused_finger_event_.reset(new TouchEvent(event));
-    tap_timer_.Start(FROM_HERE,
-                     gesture_detector_config_.double_tap_timeout,
-                     this,
-                     &TouchExplorationController::OnTapTimerFired);
-    gesture_provider_.OnTouchEvent(event);
-    gesture_provider_.OnTouchEventAck(false);
-    ProcessGestureEvents();
-    state_ = SINGLE_TAP_PRESSED;
-    VLOG_STATE();
-    return ui::EVENT_REWRITE_DISCARD;
+  if (type != ui::ET_TOUCH_PRESSED) {
+    NOTREACHED() << "Unexpected event type received: " << event.name();
+    return ui::EVENT_REWRITE_CONTINUE;
   }
-  NOTREACHED() << "Unexpected event type received: " << event.name();;
-  return ui::EVENT_REWRITE_CONTINUE;
+  int location = FindEdgesWithinBounds(event.location(), kSlopDistanceFromEdge);
+  base::TimeDelta timeout;
+
+  // If the press was at a corner, the user might go into corner passthrough
+  // instead.
+  bool in_a_bottom_corner =
+      (BOTTOM_LEFT_CORNER == location) || (BOTTOM_RIGHT_CORNER == location);
+  if (in_a_bottom_corner) {
+    VLOG(0) << "Location: " << location;
+    long_press_timer_.Start(FROM_HERE,
+                            gesture_detector_config_.longpress_timeout,
+                            this,
+                            &TouchExplorationController::OnLongPressTimerFired);
+    waiting_for_corner_passthrough_ = true;
+  } else {
+    waiting_for_corner_passthrough_ = false;
+  }
+  tap_timer_.Start(FROM_HERE,
+                   gesture_detector_config_.double_tap_timeout,
+                   this,
+                   &TouchExplorationController::OnTapTimerFired);
+  initial_press_.reset(new TouchEvent(event));
+  last_unused_finger_event_.reset(new TouchEvent(event));
+  gesture_provider_.OnTouchEvent(event);
+  gesture_provider_.OnTouchEventAck(false);
+  ProcessGestureEvents();
+  state_ = SINGLE_TAP_PRESSED;
+  VLOG_STATE();
+  return ui::EVENT_REWRITE_DISCARD;
 }
 
 ui::EventRewriteStatus TouchExplorationController::InSingleTapPressed(
     const ui::TouchEvent& event, scoped_ptr<ui::Event>* rewritten_event) {
   const ui::EventType type = event.type();
 
+  int location = FindEdgesWithinBounds(event.location(), kMaxDistanceFromEdge);
+  bool in_a_bottom_corner =
+      (location == BOTTOM_LEFT_CORNER) || (location == BOTTOM_RIGHT_CORNER);
+  // If the event is from the initial press and the location is no longer in the
+  // corner, then we are not waiting for a corner passthrough anymore.
+  if (event.touch_id() == initial_press_->touch_id() && !in_a_bottom_corner) {
+    waiting_for_corner_passthrough_ = false;
+    if (long_press_timer_.IsRunning()) {
+      long_press_timer_.Stop();
+      if (event.time_stamp() - initial_press_->time_stamp() >
+          gesture_detector_config_.double_tap_timeout) {
+        OnTapTimerFired();
+      }
+    }
+  }
+
   if (type == ui::ET_TOUCH_PRESSED) {
+    waiting_for_corner_passthrough_ = false;
     // Adding a second finger within the timeout period switches to
     // passing through every event from the second finger and none form the
     // first. The event from the first finger is still saved in initial_press_.
@@ -402,7 +450,7 @@ ui::EventRewriteStatus TouchExplorationController::InTwoToOneFinger(
     // If a third finger is pressed, we are now going into passthrough mode
     // and now need to dispatch the first finger into a press, as well as the
     // recent press.
-    if (current_touch_ids_.size() == 3){
+    if (current_touch_ids_.size() == 3) {
       state_ = PASSTHROUGH;
       scoped_ptr<ui::TouchEvent> first_finger_press;
       first_finger_press.reset(
@@ -441,6 +489,41 @@ ui::EventRewriteStatus TouchExplorationController::InTwoToOneFinger(
   return ui::EVENT_REWRITE_CONTINUE;
 }
 
+ui::EventRewriteStatus TouchExplorationController::InCornerPassthrough(
+    const ui::TouchEvent& event,
+    scoped_ptr<ui::Event>* rewritten_event) {
+  ui::EventType type = event.type();
+
+  // If the first finger has left the corner, then exit passthrough.
+  if (event.touch_id() == initial_press_->touch_id()) {
+    int edges = FindEdgesWithinBounds(event.location(), kSlopDistanceFromEdge);
+    bool in_a_bottom_corner = (edges == BOTTOM_LEFT_CORNER) ||
+                              (edges == BOTTOM_RIGHT_CORNER);
+    if (type == ui::ET_TOUCH_MOVED && in_a_bottom_corner)
+      return ui::EVENT_REWRITE_DISCARD;
+
+    if (current_touch_ids_.size() == 0) {
+      ResetToNoFingersDown();
+      return ui::EVENT_REWRITE_DISCARD;
+    }
+
+    waiting_for_corner_passthrough_ = false;
+    VLOG(0) << "Waiting for corner passthrough is false";
+    state_ = WAIT_FOR_RELEASE;
+    VLOG_STATE();
+    return ui::EVENT_REWRITE_DISCARD;
+  }
+
+  rewritten_event->reset(new ui::TouchEvent(
+      type, event.location(), event.touch_id(), event.time_stamp()));
+  (*rewritten_event)->set_flags(event.flags());
+
+  if (current_touch_ids_.size() == 0)
+    ResetToNoFingersDown();
+
+  return ui::EVENT_REWRITE_REWRITTEN;
+}
+
 ui::EventRewriteStatus TouchExplorationController::InPassthrough(
     const ui::TouchEvent& event,
     scoped_ptr<ui::Event>* rewritten_event) {
@@ -508,6 +591,7 @@ ui::EventRewriteStatus TouchExplorationController::InTouchExploreSecondPress(
 ui::EventRewriteStatus TouchExplorationController::InWaitForRelease(
     const ui::TouchEvent& event,
     scoped_ptr<ui::Event>* rewritten_event) {
+  waiting_for_corner_passthrough_ = false;
   ui::EventType type = event.type();
   if (!(type == ui::ET_TOUCH_PRESSED || type == ui::ET_TOUCH_MOVED ||
         type == ui::ET_TOUCH_RELEASED || type == ui::ET_TOUCH_CANCELLED)) {
@@ -595,6 +679,8 @@ void TouchExplorationController::OnTapTimerFired() {
       last_touch_exploration_.reset(new TouchEvent(*initial_press_));
       return;
     case SINGLE_TAP_PRESSED:
+      if (waiting_for_corner_passthrough_)
+        return;
     case GESTURE_IN_PROGRESS:
       // Discard any pending gestures.
       delete gesture_provider_.GetAndResetPendingGestures();
@@ -611,6 +697,16 @@ void TouchExplorationController::OnTapTimerFired() {
   last_touch_exploration_.reset(new TouchEvent(*initial_press_));
 }
 
+void TouchExplorationController::OnLongPressTimerFired() {
+  if (waiting_for_corner_passthrough_) {
+    delegate_->PlayEarCon();
+    delete gesture_provider_.GetAndResetPendingGestures();
+    state_ = CORNER_PASSTHROUGH;
+    VLOG_STATE();
+    return;
+  }
+}
+
 void TouchExplorationController::DispatchEvent(ui::Event* event) {
   if (event_handler_for_testing_) {
     event_handler_for_testing_->OnEvent(event);
@@ -805,6 +901,7 @@ void TouchExplorationController::EnterTouchToMouseMode() {
 }
 
 void TouchExplorationController::ResetToNoFingersDown() {
+  waiting_for_corner_passthrough_ = false;
   ProcessGestureEvents();
   if (sound_timer_.IsRunning())
     sound_timer_.Stop();
@@ -875,6 +972,8 @@ const char* TouchExplorationController::EnumStateToString(State state) {
       return "TOUCH_EXPLORE_SECOND_PRESS";
     case TWO_TO_ONE_FINGER:
       return "TWO_TO_ONE_FINGER";
+    case CORNER_PASSTHROUGH:
+      return "CORNER_PASSTHROUGH";
     case PASSTHROUGH:
       return "PASSTHROUGH";
     case WAIT_FOR_RELEASE: