gestures: Generate only either scroll-end or fling-start events at the end of a scroll gesture.

ui/app_list/pagination_model.cc

 // Copyright (c) 2012 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/app_list/pagination_model.h"
 
 #include <algorithm>
 
 #include "ui/app_list/pagination_model_observer.h"
 #include "ui/base/animation/slide_animation.h"
@@ skipping 38 matching lines @@
     } else if (transition_.target_page != page) {
       // If there is a running transition, remembers it if it's new.
       pending_selected_page_ = page;
     }
   } else {
     DCHECK(page >= 0 && page < total_pages_);
 
     if (page == selected_page_)
       return;
 
-    ResetTranstionAnimation();
+    ResetTransitionAnimation();
 
     int old_selected = selected_page_;
     selected_page_ = page;
     NotifySelectedPageChanged(old_selected, selected_page_);
   }
 }
 
 void PaginationModel::SelectPageRelative(int delta, bool animate) {
   SelectPage(CalculateTargetPage(delta), animate);
 }
 
 void PaginationModel::SetTransition(const Transition& transition) {
   // -1 and |total_pages_| is a valid target page, which means user is at
   // the end and there is no target page for this scroll.
   DCHECK(transition.target_page >= -1 &&
          transition.target_page <= total_pages_);
   DCHECK(transition.progress >= 0 && transition.progress <= 1);
 
   if (transition_.Equals(transition))
     return;
 
   transition_ = transition;
   NotifyTransitionChanged();
 }
 
 void PaginationModel::SetTransitionDuration(int duration_ms) {
   transition_duration_ms_ = duration_ms;
 }
 
+void PaginationModel::ResetTransitionAnimation() {
+  transition_animation_.reset();
+  transition_.target_page = -1;
+  transition_.progress = 0;
+  pending_selected_page_ = -1;
+}
+
 void PaginationModel::StartScroll() {
   // Cancels current transition animation (if any).
   transition_animation_.reset();
 }
 
 void PaginationModel::UpdateScroll(double delta) {
   // Translates scroll delta to desired page change direction.
   int page_change_dir = delta > 0 ? -1 : 1;
 
   // Initializes a transition if there is none.
@@ skipping 79 matching lines @@
   CreateTransitionAnimation();
   transition_animation_->Show();
 }
 
 void PaginationModel::CreateTransitionAnimation() {
   transition_animation_.reset(new ui::SlideAnimation(this));
   if (transition_duration_ms_)
     transition_animation_->SetSlideDuration(transition_duration_ms_);
 }
 
-void PaginationModel::ResetTranstionAnimation() {
-  transition_animation_.reset();
-  transition_.target_page = -1;
-  transition_.progress = 0;
-  pending_selected_page_ = -1;
-}
-
 void PaginationModel::AnimationProgressed(const ui::Animation* animation) {
   transition_.progress = transition_animation_->GetCurrentValue();
   NotifyTransitionChanged();
 }
 
 void PaginationModel::AnimationEnded(const ui::Animation* animation) {
   // Save |pending_selected_page_| because SelectPage resets it.
   int next_target = pending_selected_page_;
 
   if (transition_animation_->GetCurrentValue() == 1) {
     // Showing animation ends.
     int target_page = transition_.target_page;
 
     // If target page is not in valid range, reverse the animation.
     if (target_page < 0 || target_page >= total_pages_) {
       transition_animation_->Hide();
       return;
     }
 
     // Otherwise, change page and finish the transition.
     DCHECK(selected_page_ != transition_.target_page);
     SelectPage(transition_.target_page, false /* animate */);
   } else if (transition_animation_->GetCurrentValue() == 0) {
     // Hiding animation ends. No page change should happen.
-    ResetTranstionAnimation();
+    ResetTransitionAnimation();
   }
 
   if (next_target >= 0)
     SelectPage(next_target, true);
 }
 
 }  // namespace app_list