Eliminate pinch drift by removing touch radius from span calculation

ui/gfx/android/view_configuration.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/gfx/android/view_configuration.h"
 
 #include "base/android/context_utils.h"
 #include "base/android/jni_android.h"
 #include "base/lazy_instance.h"
 #include "base/macros.h"
@@ skipping 10 matching lines @@
 struct ViewConfigurationData {
   ViewConfigurationData()
       : double_tap_timeout_in_ms_(0),
         long_press_timeout_in_ms_(0),
         tap_timeout_in_ms_(0),
         scroll_friction_(1.f),
         max_fling_velocity_in_dips_s_(0),
         min_fling_velocity_in_dips_s_(0),
         touch_slop_in_dips_(0),
         double_tap_slop_in_dips_(0),
-        min_scaling_span_in_dips_(0),
-        min_scaling_touch_major_in_dips_(0) {
+        min_scaling_span_in_dips_(0) {
     JNIEnv* env = AttachCurrentThread();
     j_view_configuration_helper_.Reset(
         Java_ViewConfigurationHelper_createWithListener(
             env, base::android::GetApplicationContext()));
 
     double_tap_timeout_in_ms_ =
         Java_ViewConfigurationHelper_getDoubleTapTimeout(env);
     long_press_timeout_in_ms_ =
         Java_ViewConfigurationHelper_getLongPressTimeout(env);
     tap_timeout_in_ms_ = Java_ViewConfigurationHelper_getTapTimeout(env);
     scroll_friction_ = Java_ViewConfigurationHelper_getScrollFriction(env);
 
     jobject obj = j_view_configuration_helper_.obj();
     Update(Java_ViewConfigurationHelper_getMaximumFlingVelocity(env, obj),
            Java_ViewConfigurationHelper_getMinimumFlingVelocity(env, obj),
            Java_ViewConfigurationHelper_getTouchSlop(env, obj),
            Java_ViewConfigurationHelper_getDoubleTapSlop(env, obj),
-           Java_ViewConfigurationHelper_getMinScalingSpan(env, obj),
-           Java_ViewConfigurationHelper_getMinScalingTouchMajor(env, obj));
+           Java_ViewConfigurationHelper_getMinScalingSpan(env, obj));
   }
 
   ~ViewConfigurationData() {}
 
   void SynchronizedUpdate(float maximum_fling_velocity,
                           float minimum_fling_velocity,
                           float touch_slop,
                           float double_tap_slop,
-                          float min_scaling_span,
-                          float min_scaling_touch_major) {
+                          float min_scaling_span) {
     base::AutoLock autolock(lock_);
     Update(maximum_fling_velocity, minimum_fling_velocity, touch_slop,
-           double_tap_slop, min_scaling_span, min_scaling_touch_major);
+           double_tap_slop, min_scaling_span);
   }
 
   int double_tap_timeout_in_ms() const { return double_tap_timeout_in_ms_; }
   int long_press_timeout_in_ms() const { return long_press_timeout_in_ms_; }
   int tap_timeout_in_ms() const { return tap_timeout_in_ms_; }
   float scroll_friction() const { return scroll_friction_; }
 
   int max_fling_velocity_in_dips_s() {
     base::AutoLock autolock(lock_);
     return max_fling_velocity_in_dips_s_;
@@ skipping 12 matching lines @@
   int double_tap_slop_in_dips() {
     base::AutoLock autolock(lock_);
     return double_tap_slop_in_dips_;
   }
 
   int min_scaling_span_in_dips() {
     base::AutoLock autolock(lock_);
     return min_scaling_span_in_dips_;
   }
 
-  int min_scaling_touch_major_in_dips() {
-    base::AutoLock autolock(lock_);
-    return min_scaling_touch_major_in_dips_;
-  }
-
  private:
   void Update(float maximum_fling_velocity,
               float minimum_fling_velocity,
               float touch_slop,
               float double_tap_slop,
-              float min_scaling_span,
-              float min_scaling_touch_major) {
+              float min_scaling_span) {
     DCHECK_LE(minimum_fling_velocity, maximum_fling_velocity);
     max_fling_velocity_in_dips_s_ = maximum_fling_velocity;
     min_fling_velocity_in_dips_s_ = minimum_fling_velocity;
     touch_slop_in_dips_ = touch_slop;
     double_tap_slop_in_dips_ = double_tap_slop;
     min_scaling_span_in_dips_ = min_scaling_span;
-    min_scaling_touch_major_in_dips_ = min_scaling_touch_major;
   }
 
   base::Lock lock_;
   base::android::ScopedJavaGlobalRef<jobject> j_view_configuration_helper_;
 
   // These values will remain constant throughout the lifetime of the app, so
   // read-access needn't be synchronized.
   int double_tap_timeout_in_ms_;
   int long_press_timeout_in_ms_;
   int tap_timeout_in_ms_;
   float scroll_friction_;
 
   // These values may vary as view-specific parameters change, so read/write
   // access must be synchronized.
   int max_fling_velocity_in_dips_s_;
   int min_fling_velocity_in_dips_s_;
   int touch_slop_in_dips_;
   int double_tap_slop_in_dips_;
   int min_scaling_span_in_dips_;
-  int min_scaling_touch_major_in_dips_;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(ViewConfigurationData);
 };
 
 // Leaky to allow access from any thread.
 base::LazyInstance<ViewConfigurationData>::Leaky g_view_configuration =
     LAZY_INSTANCE_INITIALIZER;
 
 }  // namespace
 
 static void UpdateSharedViewConfiguration(JNIEnv* env,
                                           const JavaParamRef<jobject>& obj,
                                           jfloat maximum_fling_velocity,
                                           jfloat minimum_fling_velocity,
                                           jfloat touch_slop,
                                           jfloat double_tap_slop,
-                                          jfloat min_scaling_span,
-                                          jfloat min_scaling_touch_major) {
+                                          jfloat min_scaling_span) {
   g_view_configuration.Get().SynchronizedUpdate(
       maximum_fling_velocity, minimum_fling_velocity, touch_slop,
-      double_tap_slop, min_scaling_span, min_scaling_touch_major);
+      double_tap_slop, min_scaling_span);
 }
 
 int ViewConfiguration::GetDoubleTapTimeoutInMs() {
   return g_view_configuration.Get().double_tap_timeout_in_ms();
 }
 
 int ViewConfiguration::GetLongPressTimeoutInMs() {
   return g_view_configuration.Get().long_press_timeout_in_ms();
 }
 
@@ skipping 18 matching lines @@
 }
 
 int ViewConfiguration::GetDoubleTapSlopInDips() {
   return g_view_configuration.Get().double_tap_slop_in_dips();
 }
 
 int ViewConfiguration::GetMinScalingSpanInDips() {
   return g_view_configuration.Get().min_scaling_span_in_dips();
 }
 
-int ViewConfiguration::GetMinScalingTouchMajorInDips() {
-  return g_view_configuration.Get().min_scaling_touch_major_in_dips();
-}
-
 bool ViewConfiguration::RegisterViewConfiguration(JNIEnv* env) {
   return RegisterNativesImpl(env);
 }
 
 }  // namespace gfx