shelf: Allow directly dragging items from main shelf to overflow.

ash/shelf/shelf_view.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 "ash/shelf/shelf_view.h"
 
 #include <algorithm>
 #include <memory>
 
 #include "ash/ash_constants.h"
@@ skipping 1115 matching lines @@
       }
 
       bounds_animator_->StopAnimatingView(drag_view_);
       int drag_view_index = view_model_->GetIndexOfView(drag_view_);
       drag_view_->SetBoundsRect(view_model_->ideal_bounds(drag_view_index));
     }
     // Move our proxy view item.
     UpdateDragIconProxy(screen_location);
     return true;
   }
-  // Check if we are too far away from the shelf to enter the ripped off state.
-  // Determine the distance to the shelf.
+
+  // Determine if we should enter the ripped off state. We should enter if:

[msw, 2017/06/06 00:27:23]

nit: "Mark the item as dragged off the shelf if the drag distance exceeds
kRipOffDistance, or if it's dragged between the main and overflow shelf."

[sammiequon, 2017/06/06 16:21:26]

Done.

+  // 1) The item is dragged more than |kRipOffDistance| from the shelf.
+  // 2) We are on the overflow shelf and the item is dragged onto the main
+  // shelf.
+  // 3) We are on the main shelf and the item is dragged onto the overflow
+  // shelf.
   int delta = CalculateShelfDistance(screen_location);
-  if (delta > kRipOffDistance) {
+  bool enableRipOff = delta > kRipOffDistance;

[msw, 2017/06/06 00:27:23]

Use the unix_hacker naming convention in Chrome's C++ code |drag_off_shelf|, or
just use the |dragged_off_shelf_| member, or just inline the conditionals into
the if statement.

[sammiequon, 2017/06/06 16:21:26]

Done.

+  enableRipOff =
+      enableRipOff ||

[msw, 2017/06/06 00:27:23]

nit: if you keep separate statements like this, then use |= instead of = ... ||

[sammiequon, 2017/06/06 16:21:26]

Done.

+      (is_overflow_mode() &&
+       main_shelf_->GetBoundsForDragInsertInScreen().Contains(screen_location));
+  enableRipOff = enableRipOff || (!is_overflow_mode() && overflow_bubble_ &&
+                                  overflow_bubble_->IsShowing() &&
+                                  overflow_bubble_->shelf_view()
+                                      ->GetBoundsForDragInsertInScreen()
+                                      .Contains(screen_location));
+
+  if (enableRipOff) {
     // Create a proxy view item which can be moved anywhere.
     CreateDragIconProxy(event.root_location(), drag_view_->GetImage(),
                         drag_view_, gfx::Vector2d(0, 0),
                         kDragAndDropProxyScale);
     drag_view_->layer()->SetOpacity(0.0f);
     dragged_off_shelf_ = true;
     if (RemovableByRipOff(current_index) == REMOVABLE) {
       // Move the item to the front of the first panel item and hide it.
       // ShelfItemMoved() callback will handle the |view_model_| update and
       // call AnimateToIdealBounds().
@@ skipping 686 matching lines @@
   if (pointer == TOUCH &&
       (base::TimeTicks::Now() - touch_press_time_) <
           base::TimeDelta::FromMilliseconds(kTouchDragTimeThresholdMs)) {
     return false;
   }
 
   return true;
 }
 
 }  // namespace ash