Make GestureTextSelector detect its own gestures

ui/events/gesture_detection/scale_gesture_detector.h

 // 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.
 
 #ifndef UI_EVENTS_GESTURE_DETECTION_SCALE_GESTURE_DETECTOR_H_
 #define UI_EVENTS_GESTURE_DETECTION_SCALE_GESTURE_DETECTOR_H_
 
 #include "base/time/time.h"
 #include "ui/events/gesture_detection/gesture_detection_export.h"
 
 namespace ui {
 
 class MotionEvent;
+class ScaleGestureListener;
 
 // Port of ScaleGestureDetector.java from Android
 // * platform/frameworks/base/core/java/android/view/ScaleGestureDetector.java
 // * Change-Id: I3e7926a4f6f9ab4951f380bd004499c78b3bda69
 // * Please update the Change-Id as upstream Android changes are pulled.
-class ScaleGestureDetector {
+class GESTURE_DETECTION_EXPORT ScaleGestureDetector {
  public:
   struct GESTURE_DETECTION_EXPORT Config {
     Config();
     ~Config();
 
     // Distance the current span can deviate from the initial span before
     // scaling will start (in dips). The span is the diameter of the circle with
     // a radius of average pointer deviation from the focal point.
     float span_slop;
 
     // Minimum accepted value for TouchMajor while scaling (in dips).
     float min_scaling_touch_major;
 
     // Minimum span needed to initiate a scaling gesture (in dips).
     float min_scaling_span;
 
     // Minimum pinch span change before pinch occurs (in dips). See
     // crbug.com/373318.
     float min_pinch_update_span_delta;
   };
 
-  class ScaleGestureListener {
-   public:
-    virtual ~ScaleGestureListener() {}
-    virtual bool OnScale(const ScaleGestureDetector& detector,
-                         const MotionEvent& e) = 0;
-    virtual bool OnScaleBegin(const ScaleGestureDetector& detector,
-                              const MotionEvent& e) = 0;
-    virtual void OnScaleEnd(const ScaleGestureDetector& detector,
-                            const MotionEvent& e) = 0;
-  };
-
-  // A convenience class to extend when you only want to listen for a subset of
-  // scaling-related events. This implements all methods in
-  // |ScaleGestureListener| but does nothing.
-  // |OnScale()| returns false so that a subclass can retrieve the accumulated
-  // scale factor in an overridden |OnScaleEnd()|.
-  // |OnScaleBegin() returns true.
-  class SimpleScaleGestureListener : public ScaleGestureListener {
-   public:
-    // ScaleGestureListener implementation.
-    virtual bool OnScale(const ScaleGestureDetector&,
-                         const MotionEvent&) OVERRIDE;
-    virtual bool OnScaleBegin(const ScaleGestureDetector&,
-                              const MotionEvent&) OVERRIDE;
-    virtual void OnScaleEnd(const ScaleGestureDetector&,
-                            const MotionEvent&) OVERRIDE;
-  };
-
   ScaleGestureDetector(const Config& config, ScaleGestureListener* listener);
   virtual ~ScaleGestureDetector();
 
   // Accepts MotionEvents and dispatches events to a |ScaleGestureListener|
   // when appropriate.
   //
   // Note: Applications should pass a complete and consistent event stream to
   // this method. A complete and consistent event stream involves all
   // MotionEvents from the initial ACTION_DOWN to the final ACTION_UP or
   // ACTION_CANCEL.
@@ skipping 64 matching lines @@
   DoubleTapMode double_tap_mode_;
 
   bool event_before_or_above_starting_gesture_event_;
 
   DISALLOW_COPY_AND_ASSIGN(ScaleGestureDetector);
 };
 
 }  // namespace ui
 
 #endif  // UI_EVENTS_GESTURE_DETECTION_SCALE_GESTURE_DETECTOR_H_