Swipe Gestures for Accessibility

ui/chromeos/touch_exploration_controller.h

Index: ui/chromeos/touch_exploration_controller.h
diff --git a/ui/chromeos/touch_exploration_controller.h b/ui/chromeos/touch_exploration_controller.h
index aad8d4c5654611fca9cc1e2a6ae0d563282f4bf0..58bb108a509414e35665b894e3a23c4622102fa2 100644
--- a/ui/chromeos/touch_exploration_controller.h
+++ b/ui/chromeos/touch_exploration_controller.h
@@ -11,6 +11,7 @@
 #include "ui/events/event.h"
 #include "ui/events/event_rewriter.h"
 #include "ui/events/gesture_detection/gesture_detector.h"
+#include "ui/events/gestures/gesture_provider_aura.h"
 #include "ui/gfx/geometry/point.h"
 
 namespace aura {
@@ -22,6 +23,8 @@ namespace ui {
 class Event;
 class EventHandler;
 class TouchEvent;
+class GestureProviderAura;

[dmazzoni, 2014/06/23 15:50:45]

Nit: sort these (alphabetize)

+class GestureEvent;
 
 // TouchExplorationController is used in tandem with "Spoken Feedback" to
 // make the touch UI accessible.
@@ -79,7 +82,7 @@ class TouchEvent;
 // The caller is expected to retain ownership of instances of this class and
 // destroy them before |root_window| is destroyed.
 class UI_CHROMEOS_EXPORT TouchExplorationController :
-    public ui::EventRewriter {
+ public ui::EventRewriter, public ui::GestureProviderAuraClient {
  public:
   explicit TouchExplorationController(aura::Window* root_window);
   virtual ~TouchExplorationController();
@@ -107,10 +110,13 @@ class UI_CHROMEOS_EXPORT TouchExplorationController :
       const ui::TouchEvent& event, scoped_ptr<ui::Event>* rewritten_event);
   ui::EventRewriteStatus InTouchExploration(
       const ui::TouchEvent& event, scoped_ptr<ui::Event>* rewritten_event);
+  ui::EventRewriteStatus InGestureInProgress(
+      const ui::TouchEvent& event, scoped_ptr<ui::Event>* rewritten_event);
   ui::EventRewriteStatus InPassthroughMinusOne(
       const ui::TouchEvent& event, scoped_ptr<ui::Event>* rewritten_event);
   ui::EventRewriteStatus InTouchExploreSecondPress(
       const ui::TouchEvent& event, scoped_ptr<ui::Event>* rewritten_event);
+
   // This timer is started every time we get the first press event, and
   // it fires after the double-click timeout elapses (300 ms by default).
   // If the user taps and releases within 300 ms and doesn't press again,
@@ -120,6 +126,12 @@ class UI_CHROMEOS_EXPORT TouchExplorationController :
   // Dispatch a new event outside of the event rewriting flow.
   void DispatchEvent(ui::Event* event);
 
+  // The gesture provider keeps track of all the touch events after

[dmazzoni, 2014/06/23 15:50:44]

Put an extra line at the top of this comment block that says "Overridden from
GestureProviderAuraClient." This is convention we have that in any class that
inherits from one or more other classes, we always clearly identify which
functions are inheriting from which parent classes, and which ones are new. In
this case, everything is new except this one.

Here's an example of a class that inherits from two others and calls out two
overridden functions:
https://code.google.com/p/chromium/codesearch#chromium/src/ui/views/controls/...

+  // the user moves fast enough to trigger a gesture. After the user
+  // completes their gesture, this method will decide what keyboard
+  // input their gesture corresponded to.
+  void OnGestureEvent(ui::GestureEvent* gesture) OVERRIDE;
+
   scoped_ptr<ui::Event> CreateMouseMoveEvent(const gfx::PointF& location,
                                              int flags);
 
@@ -155,6 +167,9 @@ class UI_CHROMEOS_EXPORT TouchExplorationController :
     // mode until all fingers are lifted.
     TOUCH_EXPLORATION,
 
+    // We're currently making a gesture.

[dmazzoni, 2014/06/23 15:50:44]

Add a bit more detail here: explain how we enter this mode because we otherwise
would have been in touch exploration mode, but the velocity is greater than a
certain threshold, and explain when we exit this state.

+    GESTURE_IN_PROGRESS,
+
     // The user placed two or more fingers down within the grace period.
     // We're now in passthrough mode until all fingers are lifted. Initially
     // the first finger is ignored and other fingers are passed through
@@ -217,6 +232,9 @@ class UI_CHROMEOS_EXPORT TouchExplorationController :
   // timeout and pixel slop constants.
   ui::GestureDetector::Config gesture_detector_config_;
 
+  // Gesture Handler to interpret the touch events

[dmazzoni, 2014/06/23 15:50:44]

Nit: end with period.

+  ui::GestureProviderAura gesture_provider_;
+
   // The previous state entered.
   State prev_state_;