Prevent a user from hiding the shelf via a gesture when there are no visible windows

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 18 matching lines @@
 #include "ash/wm/window_properties.h"
 #include "ash/wm/window_util.h"
 #include "ash/wm/workspace_controller.h"
 #include "base/auto_reset.h"
 #include "base/command_line.h"
 #include "base/command_line.h"
 #include "base/i18n/rtl.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/strings/string_util.h"
 #include "ui/aura/client/activation_client.h"
+#include "ui/aura/client/cursor_client.h"
 #include "ui/aura/root_window.h"
 #include "ui/base/events/event.h"
 #include "ui/base/events/event_handler.h"
 #include "ui/base/ui_base_switches.h"
 #include "ui/compositor/layer.h"
 #include "ui/compositor/layer_animation_observer.h"
 #include "ui/compositor/layer_animator.h"
 #include "ui/compositor/scoped_layer_animation_settings.h"
 #include "ui/gfx/screen.h"
 #include "ui/views/widget/widget.h"
@@ skipping 224 matching lines @@
   TargetBounds target_bounds;
   CalculateTargetBounds(state_, &target_bounds);
   GetLayer(shelf_)->SetOpacity(target_bounds.opacity);
   shelf_->SetWidgetBounds(
       ScreenAsh::ConvertRectToScreen(
           shelf_->GetNativeView()->parent(),
           target_bounds.shelf_bounds_in_root));
   if (shelf_->launcher())
     shelf_->launcher()->SetLauncherViewBounds(
         target_bounds.launcher_bounds_in_shelf);
-  GetLayer(shelf_->status_area_widget())->SetOpacity(target_bounds.opacity);
+  GetLayer(shelf_->status_area_widget())->SetOpacity(
+      target_bounds.status_opacity);
   // TODO(harrym): Once status area widget is a child view of shelf
   // this can be simplified.
   gfx::Rect status_bounds = target_bounds.status_bounds_in_shelf;
   status_bounds.set_x(status_bounds.x() +
                       target_bounds.shelf_bounds_in_root.x());
   status_bounds.set_y(status_bounds.y() +
                       target_bounds.shelf_bounds_in_root.y());
   shelf_->status_area_widget()->SetBounds(
       ScreenAsh::ConvertRectToScreen(
           shelf_->status_area_widget()->GetNativeView()->parent(),
@@ skipping 270 matching lines @@
     return;
 
   State state;
   state.visibility_state = visibility_state;
   state.auto_hide_state = CalculateAutoHideState(visibility_state);
   state.is_screen_locked =
       Shell::GetInstance()->session_state_delegate()->IsScreenLocked();
   state.window_state = workspace_controller_ ?
       workspace_controller_->GetWindowState() : WORKSPACE_WINDOW_STATE_DEFAULT;
 
-  // It's possible for SetState() when a window becomes maximized but the state

[pkotwicz, 2013/08/09 00:04:34]

This comment is outdated. State::window_state now exists

-  // won't have changed value. Do the dimming check before the early exit.
-  shelf_->SetDimsShelf(
-      (state.visibility_state == SHELF_VISIBLE) &&
-      state.window_state == WORKSPACE_WINDOW_STATE_MAXIMIZED);
-
   if (state_.Equals(state))
     return;  // Nothing changed.
 
   FOR_EACH_OBSERVER(ShelfLayoutManagerObserver, observers_,
                     WillChangeVisibilityState(visibility_state));
 
   if (state.visibility_state == SHELF_AUTO_HIDE) {
     // When state is SHELF_AUTO_HIDE we need to track when the mouse is over the
     // launcher to unhide the shelf. AutoHideEventFilter does that for us.
     if (!auto_hide_event_filter_)
@@ skipping 34 matching lines @@
   // Do not animate the background when:
   // - Going from a hidden / auto hidden shelf in fullscreen to a visible shelf
   //   in maximized mode.
   // - Going from an auto hidden shelf in maximized mode to a visible shelf in
   //   maximized mode.
   if (state.visibility_state == SHELF_VISIBLE &&
       state.window_state == WORKSPACE_WINDOW_STATE_MAXIMIZED &&
       old_state.visibility_state != SHELF_VISIBLE) {
     change_type = BackgroundAnimator::CHANGE_IMMEDIATE;
   } else {
-    // Delay updating the background when going from SHELF_AUTO_HIDE_SHOWN to
-    // SHELF_AUTO_HIDE_HIDDEN until the shelf animates out. Otherwise during the
-    // animation you see the background change.
-    // Also delay the animation when the shelf was hidden, and has just been
-    // made visible (e.g. using a gesture-drag).
-    if (state.visibility_state == SHELF_AUTO_HIDE &&

[pkotwicz, 2013/08/09 00:04:34]

To the extent of my understanding this is dead code (and always has been).
ShelfLayoutManager::GetShelfBackgroundType() does not take the auto hide state
into account.

I beleive that the intention of this code is to delay the shelf background
change when in maximized mode and transitioning from a visible shelf to an auto
hidden shelf. (Making that occur is not trivial so I am leaving that bug fix for
another time but am still removing the dead code).

-        state.auto_hide_state == SHELF_AUTO_HIDE_HIDDEN &&
-        old_state.visibility_state == SHELF_AUTO_HIDE) {
-      delay_background_change = true;
-    } else if (state.visibility_state == SHELF_VISIBLE &&
-               old_state.visibility_state == SHELF_AUTO_HIDE &&
-               old_state.auto_hide_state == SHELF_AUTO_HIDE_HIDDEN) {
+    // Delay the animation when the shelf was hidden, and has just been made
+    // visible (e.g. using a gesture-drag).
+    if (state.visibility_state == SHELF_VISIBLE &&
+        old_state.visibility_state == SHELF_AUTO_HIDE &&
+        old_state.auto_hide_state == SHELF_AUTO_HIDE_HIDDEN) {
       delay_background_change = true;
     }
   }
 
   if (delay_background_change) {
     if (update_shelf_observer_)
       update_shelf_observer_->Detach();
     // UpdateShelfBackground deletes itself when the animation is done.
     update_shelf_observer_ = new UpdateShelfObserver(this);
     status_animation_setter.AddObserver(update_shelf_observer_);
+  } else {

[pkotwicz, 2013/08/09 00:04:34]

Some house cleaning.

+    UpdateShelfBackground(change_type);
   }
+
+  shelf_->SetDimsShelf(
+      (state.visibility_state == SHELF_VISIBLE) &&
+      state.window_state == WORKSPACE_WINDOW_STATE_MAXIMIZED);
+
   ui::Layer* layer = GetLayer(shelf_->status_area_widget());
   // TODO(harrym): Remove when status_area is view (crbug.com/180422).
   gfx::Rect status_bounds = target_bounds.status_bounds_in_shelf;
   status_bounds.set_x(status_bounds.x() +
                       target_bounds.shelf_bounds_in_root.x());
   status_bounds.set_y(status_bounds.y() +
                       target_bounds.shelf_bounds_in_root.y());
   layer->SetBounds(status_bounds);
   layer->SetOpacity(target_bounds.status_opacity);
   Shell::GetInstance()->SetDisplayWorkAreaInsets(
       root_window_, target_bounds.work_area_insets);
   UpdateHitTestBounds();
-  if (!delay_background_change)
-    UpdateShelfBackground(change_type);

[sadrul, 2013/08/09 05:30:13]

This change, the change between newlines 645-652, oldlines 634-645 and 574-579
are not related to fixing this bug, right? This code is sufficiently brittle and
source of a lot of subtle bugs that this kind of clean-up is best done in a
separate CL, even if it looks innocuous.

 
   // OnAutoHideStateChanged Should be emitted when:
   //  - firstly state changed to auto-hide from other state
   //  - or, auto_hide_state has changed
   if ((old_state.visibility_state != state_.visibility_state &&
        state_.visibility_state == SHELF_AUTO_HIDE) ||
       old_state.auto_hide_state != state_.auto_hide_state) {
     FOR_EACH_OBSERVER(ShelfLayoutManagerObserver, observers_,
                       OnAutoHideStateChanged(state_.auto_hide_state));
   }
@@ skipping 101 matching lines @@
         0, (dock_bounds_.x() > 0 ? dock_bounds_.width() : 0));
     target_bounds->work_area_insets += dock_insets;
   }
 
   target_bounds->opacity =
       (gesture_drag_status_ == GESTURE_DRAG_IN_PROGRESS ||
        state.visibility_state == SHELF_VISIBLE ||
        state.visibility_state == SHELF_AUTO_HIDE) ? 1.0f : 0.0f;
   target_bounds->status_opacity =
       (state.visibility_state == SHELF_AUTO_HIDE &&
-       state.auto_hide_state == SHELF_AUTO_HIDE_HIDDEN) ?
+       state.auto_hide_state == SHELF_AUTO_HIDE_HIDDEN &&
+       gesture_drag_status_ != GESTURE_DRAG_IN_PROGRESS) ?
       0.0f : target_bounds->opacity;
 
   if (gesture_drag_status_ == GESTURE_DRAG_IN_PROGRESS)
     UpdateTargetBoundsForGesture(target_bounds);
 
   // This needs to happen after calling UpdateTargetBoundsForGesture(), because
   // that can change the size of the shelf.
   target_bounds->launcher_bounds_in_shelf = SelectValueForShelfAlignment(
       gfx::Rect(base::i18n::IsRTL() ? status_size.width() : 0, 0,
                     shelf_width - status_size.width(),
@@ skipping 131 matching lines @@
   // TODO: Figure out if we need any special handling when the keyboard is
   // visible.
   return show_shelf_region_in_screen;
 }
 
 ShelfAutoHideState ShelfLayoutManager::CalculateAutoHideState(
     ShelfVisibilityState visibility_state) const {
   if (visibility_state != SHELF_AUTO_HIDE || !shelf_)
     return SHELF_AUTO_HIDE_HIDDEN;
 
-  if (gesture_drag_status_ == GESTURE_DRAG_COMPLETE_IN_PROGRESS)
-    return gesture_drag_auto_hide_state_;
-
   Shell* shell = Shell::GetInstance();
   if (shell->GetAppListTargetVisibility())
     return SHELF_AUTO_HIDE_SHOWN;
 
   if (shelf_->status_area_widget() &&
       shelf_->status_area_widget()->ShouldShowLauncher())
     return SHELF_AUTO_HIDE_SHOWN;
 
   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;
 
+  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()) {
     // Increase the the hit test area to prevent the shelf from disappearing
     // when the mouse is over the bubble gap.
     shelf_region.Inset(alignment_ == SHELF_ALIGNMENT_RIGHT ?
                            -kNotificationBubbleGapHeight : 0,
                        alignment_ == SHELF_ALIGNMENT_BOTTOM ?
                            -kNotificationBubbleGapHeight : 0,
@@ skipping 20 matching lines @@
   // shelf slightly to make it easier to show the shelf in this situation. We
   // do not check |auto_hide_timer_|.IsRunning() because it returns false when
   // the timer's task is running.
   if ((state_.auto_hide_state == SHELF_AUTO_HIDE_SHOWN ||
        mouse_over_shelf_when_auto_hide_timer_started_) &&
       GetAutoHideShowShelfRegionInScreen().Contains(
           cursor_position_in_screen)) {
     return SHELF_AUTO_HIDE_SHOWN;
   }
 
-  const std::vector<aura::Window*> windows =
-      ash::MruWindowTracker::BuildWindowList(false);
-
-  // Process the window list and check if there are any visible windows.
-  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())
-      return SHELF_AUTO_HIDE_HIDDEN;
-  }
-
-  // If there are no visible windows do not hide the shelf.
-  return SHELF_AUTO_HIDE_SHOWN;
+  return SHELF_AUTO_HIDE_HIDDEN;
 }
 
 void ShelfLayoutManager::UpdateHitTestBounds() {
   gfx::Insets mouse_insets;
   gfx::Insets touch_insets;
   if (state_.visibility_state == SHELF_VISIBLE) {
     // Let clicks at the very top of the launcher through so windows can be
     // resized with the bottom-right corner and bottom edge.
     mouse_insets = GetInsetsForAlignment(kWorkspaceAreaVisibleInset);
   } else if (state_.visibility_state == SHELF_AUTO_HIDE) {
@@ skipping 55 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