Inject vr controller events into Android Native UI.

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 <algorithm>
 #include <cmath>
 #include <utility>
 
@@ skipping 235 matching lines @@
       break;
     // User has not started a gesture (by moving out of slop).
     case TOUCHING:
       HandleDetectingState(gesture);
       break;
     // User is scrolling on touchpad
     case SCROLLING:
       HandleScrollingState(gesture);
       break;
     default:
-      LOG(ERROR) << "Wrong gesture detector state: " << state_;
+      NOTREACHED();
       break;
   }
 }
 
 void VrController::HandleWaitingState(WebGestureEvent* gesture) {
   // User puts finger on touch pad (or when the touch down for current gesture
   // is missed, initiate gesture from current touch point).
   if (touch_info_->touch_down || touch_info_->is_touching) {
     // update initial touchpoint
     *init_touch_point_ = touch_info_->touch_point;
@@ skipping 13 matching lines @@
     return;
   }
 
   // Touch position is changed, the touch point moves outside of slop,
   // and the Controller's button is not down.
   if (touch_position_changed_ && touch_info_->is_touching &&
       !InSlop(touch_info_->touch_point.position) &&
       !ButtonDownHappened(gvr::kControllerButtonClick)) {
     state_ = SCROLLING;
     gesture->setType(WebInputEvent::GestureScrollBegin);
-    UpdateGesture(gesture);
+    UpdateGestureParameters();
     gesture->data.scrollBegin.deltaXHint =
         displacement_.x * kDisplacementScaleFactor;
     gesture->data.scrollBegin.deltaYHint =
         displacement_.y * kDisplacementScaleFactor;
+    gesture->data.scrollBegin.deltaHintUnits =
+        blink::WebGestureEvent::ScrollUnits::PrecisePixels;
   }
 }
 
 void VrController::HandleScrollingState(WebGestureEvent* gesture) {
   if (touch_info_->touch_up || !(touch_info_->is_touching) ||
       ButtonDownHappened(gvr::kControllerButtonClick)) {
     // Gesture ends.
     gesture->setType(WebInputEvent::GestureScrollEnd);
-    UpdateGesture(gesture);
+    UpdateGestureParameters();
   } else if (touch_position_changed_) {
     // User continues scrolling and there is a change in touch position.
     gesture->setType(WebInputEvent::GestureScrollUpdate);
-    UpdateGesture(gesture);
+    UpdateGestureParameters();
     if (IsHorizontalGesture()) {
       gesture->data.scrollUpdate.deltaX =
           displacement_.x * kDisplacementScaleFactor;
     } else {
       gesture->data.scrollUpdate.deltaY =
           displacement_.y * kDisplacementScaleFactor;
     }
     last_velocity_ = overall_velocity_;
   }
 }
@@ skipping 15 matching lines @@
 
   // Reset the pointers.
   prev_touch_point_.reset(new TouchPoint);
   cur_touch_point_.reset(new TouchPoint);
   init_touch_point_.reset(new TouchPoint);
   touch_info_.reset(new TouchInfo);
   Vector::SetZero(&overall_velocity_);
   Vector::SetZero(&last_velocity_);
 }
 
-void VrController::UpdateGesture(WebGestureEvent* gesture) {
-  if (!gesture)
-    LOG(ERROR) << "The gesture pointer is not initiated properly.";
+void VrController::UpdateGestureParameters() {
   displacement_ = Vector::Subtract(touch_info_->touch_point.position,
                                    prev_touch_point_->position);
 }
 
 bool VrController::UpdateCurrentTouchpoint() {
   touch_info_->touch_up = TouchUpHappened();
   touch_info_->touch_down = TouchDownHappened();
   touch_info_->is_touching = IsTouching();
   touch_info_->touch_point.position.x = TouchPosX();
   touch_info_->touch_point.position.y = TouchPosY();
@@ skipping 30 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