Reland: Implement Aura side of unified touch text selection for contents

ui/touch_selection/touch_selection_controller.h

Index: ui/touch_selection/touch_selection_controller.h
diff --git a/ui/touch_selection/touch_selection_controller.h b/ui/touch_selection/touch_selection_controller.h
index 115dd0d637046b44aa49c42e832fc5e82489cc95..b5879c10f322e9be1f0dd0c2314934fd164ba514 100644
--- a/ui/touch_selection/touch_selection_controller.h
+++ b/ui/touch_selection/touch_selection_controller.h
@@ -30,6 +30,8 @@ class UI_TOUCH_SELECTION_EXPORT TouchSelectionControllerClient {
                                         const gfx::PointF& extent) = 0;
   virtual void OnSelectionEvent(SelectionEventType event) = 0;
   virtual scoped_ptr<TouchHandleDrawable> CreateDrawable() = 0;
+  virtual void OnScrollStarted() = 0;
+  virtual void OnScrollCompleted() = 0;
 };
 
 // Controller for manipulating text selection via touch input.
@@ -42,10 +44,11 @@ class UI_TOUCH_SELECTION_EXPORT TouchSelectionController
                            bool show_on_tap_for_empty_editable);
   ~TouchSelectionController() override;
 
-  // To be called when the selection bounds have changed.
+  // To be called when the selection bounds info has been updated.
   // Note that such updates will trigger handle updates only if preceded
   // by an appropriate call to allow automatic showing.
-  void OnSelectionBoundsChanged(const SelectionBound& start,
+  // Return value specifies if anything has been updated or not.
+  bool OnSelectionBoundsUpdated(const SelectionBound& start,
                                 const SelectionBound& end);
 
   // Allows touch-dragging of the handle.
@@ -78,6 +81,9 @@ class UI_TOUCH_SELECTION_EXPORT TouchSelectionController
   // To be called when the contents of the focused region changes.
   void OnSelectionEmpty(bool empty);
 
+  // To be called when native view moves around.
+  void OnNativeViewMoved();
+
   // Ticks an active animation, as requested to the client by |SetNeedsAnimate|.
   // Returns true if an animation is active and requires further ticking.
   bool Animate(base::TimeTicks animate_time);
@@ -97,6 +103,12 @@ class UI_TOUCH_SELECTION_EXPORT TouchSelectionController
   const gfx::PointF& GetStartPosition() const;
   const gfx::PointF& GetEndPosition() const;
 
+  const SelectionBound& start() const { return start_; }
+  const SelectionBound& end() const { return end_; }
+
+  bool is_insertion_active() const { return is_insertion_active_; }
+  bool is_selection_active() const { return is_selection_active_; }
+
  private:
   enum InputEventType { TAP, LONG_PRESS, INPUT_EVENT_TYPE_NONE };