Provide max gesture bounds and option to ignore touch size during pinch

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/memory/scoped_ptr.h"
 #include "base/time/time.h"
 #include "ui/events/gesture_detection/gesture_detection_export.h"
@@ skipping 13 matching lines @@
     Config();
     ~Config();
     GestureDetector::Config gesture_detector_config;
 
     // 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;
 
+    // Whether to use touch major values when determining the scale span.
+    // Defaults to false.
+    bool use_touch_major_in_span;
+
     // Whether double-tap drag scaling is enabled.
     bool quick_scale_enabled;
 
     // Minimum pinch span change before pinch occurs (in dips). See
     // crbug.com/373318.
     float min_pinch_update_span_delta;
   };
 
   class ScaleGestureListener {
    public:
@@ skipping 85 matching lines @@
   float curr_span_y_;
   float prev_span_x_;
   float prev_span_y_;
   base::TimeTicks curr_time_;
   base::TimeTicks prev_time_;
   bool in_progress_;
   float span_slop_;
   float min_span_;
 
   // Bounds for recently seen values.
+  bool use_touch_major_in_span_;
   float touch_upper_;
   float touch_lower_;
   float touch_history_last_accepted_;
   int touch_history_direction_;
   base::TimeTicks touch_history_last_accepted_time_;
   float touch_min_major_;
+  float touch_max_major_;
   float double_tap_focus_x_;
   float double_tap_focus_y_;
   DoubleTapMode double_tap_mode_;
 
   bool event_before_or_above_starting_gesture_event_;
 
   scoped_ptr<GestureDetector> gesture_detector_;
 
   DISALLOW_COPY_AND_ASSIGN(ScaleGestureDetector);
 };
 
 }  // namespace ui
 
 #endif  // UI_EVENTS_GESTURE_DETECTION_SCALE_GESTURE_DETECTOR_H_