Make GestureTextSelector detect its own gestures

ui/events/gesture_detection/scale_gesture_detector.cc

 // 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.
 
 #include "ui/events/gesture_detection/scale_gesture_detector.h"
 
 #include <limits.h>
 #include <cmath>
 
 #include "base/float_util.h"
 #include "base/logging.h"
 #include "ui/events/gesture_detection/motion_event.h"
+#include "ui/events/gesture_detection/scale_gesture_listeners.h"
 
 using base::TimeDelta;
 using base::TimeTicks;
 
 namespace ui {
 namespace {
 
 // Using a small epsilon when comparing slop distances allows pixel perfect
 // slop determination when using fractional DPI coordinates (assuming the slop
 // region and DPI scale are reasonably proportioned).
 const float kSlopEpsilon = .05f;
 
 const int kTouchStabilizeTimeMs = 128;
 
 const float kScaleFactor = .5f;
 
 }  // namespace
 
 // Note: These constants were taken directly from the default (unscaled)
 // versions found in Android's ViewConfiguration.
 ScaleGestureDetector::Config::Config()
     : span_slop(16),
       min_scaling_touch_major(48),
       min_scaling_span(200),
       min_pinch_update_span_delta(0) {
 }
 
 ScaleGestureDetector::Config::~Config() {}
 
-bool ScaleGestureDetector::SimpleScaleGestureListener::OnScale(
-    const ScaleGestureDetector&, const MotionEvent&) {
-  return false;
-}
-
-bool ScaleGestureDetector::SimpleScaleGestureListener::OnScaleBegin(
-    const ScaleGestureDetector&, const MotionEvent&) {
-  return true;
-}
-
-void ScaleGestureDetector::SimpleScaleGestureListener::OnScaleEnd(
-    const ScaleGestureDetector&, const MotionEvent&) {}
-
 ScaleGestureDetector::ScaleGestureDetector(const Config& config,
                                            ScaleGestureListener* listener)
     : listener_(listener),
       focus_x_(0),
       focus_y_(0),
       curr_span_(0),
       prev_span_(0),
       initial_span_(0),
       curr_span_x_(0),
       curr_span_y_(0),
@@ skipping 292 matching lines @@
   touch_history_last_accepted_time_ = base::TimeTicks();
 }
 
 void ScaleGestureDetector::ResetScaleWithSpan(float span) {
   in_progress_ = false;
   initial_span_ = span;
   double_tap_mode_ = DOUBLE_TAP_MODE_NONE;
 }
 
 }  // namespace ui