Do not show auto-hidden shelf when dragging a window

ash/shelf/shelf_layout_manager.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_layout_manager.h"
 
 #include <algorithm>
 #include <cmath>
 #include <cstring>
 #include <string>
@@ skipping 980 matching lines @@
 
   if (shelf_->launcher() && shelf_->launcher()->IsShowingMenu())
     return SHELF_AUTO_HIDE_SHOWN;
 
   if (shelf_->launcher() && shelf_->launcher()->IsShowingOverflowBubble())
     return SHELF_AUTO_HIDE_SHOWN;
 
   if (shelf_->IsActive() || shelf_->status_area_widget()->IsActive())
     return SHELF_AUTO_HIDE_SHOWN;
 
+  // Don't show if the user is dragging the mouse.
+  if (auto_hide_event_filter_.get() && auto_hide_event_filter_->in_mouse_drag())
+    return SHELF_AUTO_HIDE_HIDDEN;

[flackr, 2013/09/16 20:55:06]

Won't this only work for mouse drags and not touch? I'm also concerned that
hiding when in a mouse drag may be the wrong thing to do if there are actually
no windows. I.e. wouldn't it hide the shelf for the duration of the drag when
starting a mouse drag with no windows?

[varkha, 2013/09/17 04:36:43]

Correct on both accounts. Dragging on empty desktop only hides when touching the
screen edge.

+
   const std::vector<aura::Window*> windows =
       ash::MruWindowTracker::BuildWindowList(false);
 
   // Process the window list and check if there are any visible windows.
   bool visible_window = false;
   for (size_t i = 0; i < windows.size(); ++i) {
     if (windows[i] && windows[i]->IsVisible() &&
         !ash::wm::IsWindowMinimized(windows[i]) &&
         root_window_ == windows[i]->GetRootWindow()) {
       visible_window = true;
       break;
     }
   }
   // If there are no visible windows do not hide the shelf.
   if (!visible_window)
     return SHELF_AUTO_HIDE_SHOWN;
 
   if (gesture_drag_status_ == GESTURE_DRAG_COMPLETE_IN_PROGRESS)
     return gesture_drag_auto_hide_state_;
 
-  // Don't show if the user is dragging the mouse.
-  if (auto_hide_event_filter_.get() && auto_hide_event_filter_->in_mouse_drag())
-    return SHELF_AUTO_HIDE_HIDDEN;
-
   // Ignore the mouse position if mouse events are disabled.
   aura::client::CursorClient* cursor_client = aura::client::GetCursorClient(
       shelf_->GetNativeWindow()->GetRootWindow());
   if (!cursor_client->IsMouseEventsEnabled())
     return SHELF_AUTO_HIDE_HIDDEN;
 
   gfx::Rect shelf_region = shelf_->GetWindowBoundsInScreen();
   if (shelf_->status_area_widget() &&
       shelf_->status_area_widget()->IsMessageBubbleShown() &&
       IsVisible()) {
@@ skipping 114 matching lines @@
       return gfx::Insets(0, distance, 0, 0);
     case SHELF_ALIGNMENT_TOP:
       return gfx::Insets(0, 0, distance, 0);
   }
   NOTREACHED();
   return gfx::Insets();
 }
 
 }  // namespace internal
 }  // namespace ash