Make page switch on drag happen at top and bottom for experimental app list.

ui/app_list/views/apps_grid_view.cc

Index: ui/app_list/views/apps_grid_view.cc
diff --git a/ui/app_list/views/apps_grid_view.cc b/ui/app_list/views/apps_grid_view.cc
index 9acafda03ed81728577f8b60b4562f3a0fdf151c..acd5d2e087bd47c0b7845d1af3bc3471297f0342 100644
--- a/ui/app_list/views/apps_grid_view.cc
+++ b/ui/app_list/views/apps_grid_view.cc
@@ -1652,22 +1652,30 @@ void AppsGridView::MaybeStartPageFlipTimer(const gfx::Point& drag_point) {
     StopPageFlipTimer();
   int new_page_flip_target = -1;
 
-  if (page_switcher_view_ &&
-      page_switcher_view_->bounds().Contains(drag_point)) {
-    gfx::Point page_switcher_point(drag_point);
-    views::View::ConvertPointToTarget(this, page_switcher_view_,
-                                      &page_switcher_point);
-    new_page_flip_target =
-        page_switcher_view_->GetPageForPoint(page_switcher_point);
-  }
+  // The drag zones are at the top and bottom of the experimental app list and
+  // on the sides and page switcher of the normal app list.
+  if (switches::IsExperimentalAppListEnabled()) {

[Matt Giuca, 2014/09/02 08:26:34]

This should be:

if (pagination_controller_->scroll_axis() ==
PaginationController::SCROLL_AXIS_HORIZONTAL)

for consistency with the other code that is conditional on scroll axis.

[calamity, 2014/09/03 11:25:36]

Done.

+    if (drag_point.y() < kPageFlipZoneSize)

[Matt Giuca, 2014/09/02 08:26:34]

I'm confused as to why this code is completely different to the horizontal
dragging code?

I mean ... they both seem to get the job done, but why are they different?

[Matt Giuca, 2014/09/03 08:02:18]

You explained this to me, so ignore it.

[calamity, 2014/09/03 11:25:36]

Acknowledged.

+      new_page_flip_target = pagination_model_.selected_page() - 1;
+    else if (drag_point.y() > height() - kPageFlipZoneSize)
+      new_page_flip_target = pagination_model_.selected_page() + 1;
+  } else {
+    if (page_switcher_view_->bounds().Contains(drag_point)) {
+      gfx::Point page_switcher_point(drag_point);
+      views::View::ConvertPointToTarget(
+          this, page_switcher_view_, &page_switcher_point);
+      new_page_flip_target =
+          page_switcher_view_->GetPageForPoint(page_switcher_point);
+    }
 
-  // TODO(xiyuan): Fix this for RTL.
-  if (new_page_flip_target == -1 && drag_point.x() < kPageFlipZoneSize)
-    new_page_flip_target = pagination_model_.selected_page() - 1;
+    // TODO(xiyuan): Fix this for RTL.
+    if (new_page_flip_target == -1 && drag_point.x() < kPageFlipZoneSize)
+      new_page_flip_target = pagination_model_.selected_page() - 1;
 
-  if (new_page_flip_target == -1 &&
-      drag_point.x() > width() - kPageFlipZoneSize) {
-    new_page_flip_target = pagination_model_.selected_page() + 1;
+    if (new_page_flip_target == -1 &&
+        drag_point.x() > width() - kPageFlipZoneSize) {
+      new_page_flip_target = pagination_model_.selected_page() + 1;
+    }
   }
 
   if (new_page_flip_target == page_flip_target_)