Cleanup shelf initialization and observation.

ash/shelf/shelf.cc

 // Copyright 2013 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.h"
 
 #include <algorithm>
 #include <cmath>
 
 #include "ash/focus_cycler.h"
@@ skipping 24 matching lines @@
 #include "ui/views/widget/widget_delegate.h"
 #include "ui/wm/public/activation_client.h"
 
 namespace ash {
 
 const char Shelf::kNativeViewName[] = "ShelfView";
 
 Shelf::Shelf(ShelfModel* shelf_model,
              ShelfDelegate* shelf_delegate,
              ShelfWidget* shelf_widget)
-    : shelf_view_(NULL),
-      alignment_(shelf_widget->GetAlignment()),
+    : shelf_view_(nullptr),
+      alignment_(SHELF_ALIGNMENT_BOTTOM),
+      auto_hide_behavior_(SHELF_AUTO_HIDE_BEHAVIOR_NEVER),
       delegate_(shelf_delegate),
       shelf_widget_(shelf_widget) {
   shelf_view_ = new ShelfView(shelf_model, delegate_, this);
   shelf_view_->Init();
   shelf_widget_->GetContentsView()->AddChildView(shelf_view_);
   shelf_widget_->GetNativeView()->SetName(kNativeViewName);
-  delegate_->OnShelfCreated(this);
 }
 
 Shelf::~Shelf() {
   delegate_->OnShelfDestroyed(this);
 }
 
 // static
 Shelf* Shelf::ForPrimaryDisplay() {
   return Shelf::ForWindow(Shell::GetPrimaryRootWindow());
 }
 
 // static
 Shelf* Shelf::ForWindow(const aura::Window* window) {
   ShelfWidget* shelf_widget = RootWindowController::ForWindow(window)->shelf();
-  return shelf_widget ? shelf_widget->shelf() : NULL;
+  return shelf_widget ? shelf_widget->shelf() : nullptr;
 }
 
 void Shelf::SetAlignment(ShelfAlignment alignment) {
+  if (alignment_ == alignment)
+    return;
+
   alignment_ = alignment;
   shelf_view_->OnShelfAlignmentChanged();
+  shelf_widget_->OnShelfAlignmentChanged();
+  delegate_->OnShelfAlignmentChanged(this);
+  Shell::GetInstance()->OnShelfAlignmentChanged(
+      shelf_widget_->GetNativeWindow()->GetRootWindow());
   // ShelfLayoutManager will resize the shelf.
 }
 
+ShelfAlignment Shelf::GetAlignment() const {
+  // Bottom alignment is forced when the screen is locked or a user gets added.
+  bool locked = shelf_widget_->shelf_layout_manager()->IsAlignmentLocked();
+  return locked ? SHELF_ALIGNMENT_BOTTOM : alignment_;

[sky, 2016/04/04 22:44:32]

Seems unusual to force an alignment like this. Couldn't the code explicitly set
the alignment to bottom when necessary? Doing that ensures delegates and what
not are notified when locking if the alignment wasn't bottom.

+}
+
 bool Shelf::IsHorizontalAlignment() const {
   return alignment_ == SHELF_ALIGNMENT_BOTTOM;
 }
 
-void Shelf::SetAutoHideBehavior(ShelfAutoHideBehavior behavior) {
-  shelf_widget_->shelf_layout_manager()->SetAutoHideBehavior(behavior);
+void Shelf::SetAutoHideBehavior(ShelfAutoHideBehavior auto_hide_behavior) {
+  if (auto_hide_behavior_ == auto_hide_behavior)
+    return;
+
+  auto_hide_behavior_ = auto_hide_behavior;
+  delegate_->OnShelfAutoHideBehaviorChanged(this);
+  Shell::GetInstance()->OnShelfAutoHideBehaviorChanged(
+      shelf_widget_->GetNativeWindow()->GetRootWindow());
 }
 
 ShelfAutoHideBehavior Shelf::GetAutoHideBehavior() const {
-  return shelf_widget_->shelf_layout_manager()->auto_hide_behavior();
+  return auto_hide_behavior_;
 }
 
 gfx::Rect Shelf::GetScreenBoundsOfItemIconForWindow(
     const aura::Window* window) {
   ShelfID id = GetShelfIDForWindow(window);
   gfx::Rect bounds(shelf_view_->GetIdealBoundsOfItemIcon(id));
   gfx::Point screen_origin;
   views::View::ConvertPointToScreen(shelf_view_, &screen_origin);
   return gfx::Rect(screen_origin.x() + bounds.x(),
                    screen_origin.y() + bounds.y(),
@@ skipping 89 matching lines @@
 
 gfx::Rect Shelf::GetVisibleItemsBoundsInScreen() const {
   return shelf_view_->GetVisibleItemsBoundsInScreen();
 }
 
 app_list::ApplicationDragAndDropHost* Shelf::GetDragAndDropHostForAppList() {
   return shelf_view_;
 }
 
 }  // namespace ash