Implement touch exploration touch typing

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 6fce4a307e29cec40ad781971561826bce3df3f9..0a624cd932963079d84858c0d4806be7e4d54450 100644
--- a/ui/chromeos/touch_exploration_controller.cc
+++ b/ui/chromeos/touch_exploration_controller.cc
@@ -72,6 +72,11 @@ void TouchExplorationController::SetExcludeBounds(const gfx::Rect& bounds) {
   exclude_bounds_ = bounds;
 }
 
+void TouchExplorationController::SetLiftActivationBounds(
+    const gfx::Rect& bounds) {
+  lift_activation_bounds_ = bounds;
+}
+
 ui::EventRewriteStatus TouchExplorationController::RewriteEvent(
     const ui::Event& event,
     std::unique_ptr<ui::Event>* rewritten_event) {
@@ -473,6 +478,12 @@ ui::EventRewriteStatus TouchExplorationController::InTouchExploration(
   } else if (type == ui::ET_TOUCH_RELEASED || type == ui::ET_TOUCH_CANCELLED) {
     initial_press_.reset(new TouchEvent(event));
     StartTapTimer();
+    if (!lift_activation_bounds_.IsEmpty()) {
+      gfx::Point location = event.location();
+      root_window_->GetHost()->ConvertScreenInPixelsToDIP(&location);
+      if (lift_activation_bounds_.Contains(location))
+        DispatchSynthesizedTap();

[dmazzoni, 2017/05/15 21:24:34]

I think you'll want to call it from more than one state
than this. For example a quick tap without first
entering touch exploration should work too.

How about intercepting the code that sends a hover
event and have it send a click event instead?

[David Tseng, 2017/05/16 16:07:34]

Sending a click event maps to forceClickOnCurrentItem in ChromeVox which calls
doDefault (accessibility action).

Do default is not a click in Blink (as I found out) but it is simply calling
through to a node's access key action which in most cases is like a click.

However, for bare bones div's and even things with aria roles, this won't work.
That's why ChromeVox + space wasn't working when I was showing you the other
day.

We can dispatch a raw click event, but that is generally not the direction we
want to go as with context menus, sending click events can be tricky e.g. nodes
in z-coord ordering hiding other nodes.

[David Tseng, 2017/05/16 16:07:34]

Isn't a quick tap just pass through mode? i.e. it achieves the same thing.

+    }
     SET_STATE(TOUCH_EXPLORE_RELEASED);
   } else if (type != ui::ET_TOUCH_MOVED) {
     NOTREACHED();
@@ -644,11 +655,13 @@ void TouchExplorationController::SendSimulatedClick() {
     return;
   }
 
-  // If we don't have an anchor point, we can't send a simulated click.
+  DispatchSynthesizedTap();
+}
+
+void TouchExplorationController::DispatchSynthesizedTap() {

[dmazzoni, 2017/05/15 21:24:35]

Rather than splitting SendSimulatedClick into two
pieces, maybe you could just handle the anchor point -
like not setting an anchor point if it's within the
lift activation bounds? Or figure out why sending 
AX_GESTURE_CLICK doesn't work

[David Tseng, 2017/05/16 16:07:34]

Ditto.

   if (anchor_point_state_ == ANCHOR_POINT_NONE)
     return;
 
-  // Otherwise send a simulated press/release at the anchor point.
   std::unique_ptr<ui::TouchEvent> touch_press;
   touch_press.reset(new ui::TouchEvent(ui::ET_TOUCH_PRESSED, gfx::Point(),
                                        Now(),