VR: Reduce scrolling/fling speed

chrome/browser/android/vr_shell/vr_controller.cc

 // Copyright 2016 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 "chrome/browser/android/vr_shell/vr_controller.h"
 
 #include <cmath>
 
 #include "base/logging.h"
 #include "base/time/time.h"
 #include "third_party/gvr-android-sdk/src/ndk/include/vr/gvr/capi/include/gvr.h"
 #include "third_party/gvr-android-sdk/src/ndk/include/vr/gvr/capi/include/gvr_controller.h"
 
 namespace vr_shell {
 
 namespace {
 
-constexpr float kDisplacementScaleFactor = 800.0f;
+constexpr float kDisplacementScaleFactor = 300.0f;
 
 // A slop represents a small rectangular region around the first touch point of
 // a gesture.
 // If the user does not move outside of the slop, no gesture is detected.
 // Gestures start to be detected when the user moves outside of the slop.
 // Vertical distance from the border to the center of slop.
 constexpr float kSlopVertical = 0.165f;
 
 // Horizontal distance from the border to the center of slop.
 constexpr float kSlopHorizontal = 0.125f;
@@ skipping 332 matching lines @@
   gvr::Vec2f velocity = Vector::ScalarMult(displacement, 1 / duration);
 
   float weight = duration / (kRC + duration);
 
   overall_velocity_ =
       Vector::Add(Vector::ScalarMult(overall_velocity_, 1 - weight),
                   Vector::ScalarMult(velocity, weight));
 }
 
 }  // namespace vr_shell