Create Tooltip object lazily so that it gets proper drop shadow

ash/tooltips/tooltip_controller.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/tooltips/tooltip_controller.h"
 
 #include <vector>
 
 #include "ash/ash_switches.h"
 #include "ash/shell.h"
@@ skipping 167 matching lines @@
 
 ////////////////////////////////////////////////////////////////////////////////
 // TooltipController public:
 
 TooltipController::TooltipController(
     aura::client::DragDropClient* drag_drop_client)
     : drag_drop_client_(drag_drop_client),
       tooltip_window_(NULL),
       tooltip_window_at_mouse_press_(NULL),
       mouse_pressed_(false),
-      tooltip_(new Tooltip),
       tooltips_enabled_(true) {
   tooltip_timer_.Start(FROM_HERE,
       base::TimeDelta::FromMilliseconds(kTooltipTimeoutMs),
       this, &TooltipController::TooltipTimerFired);
   DCHECK(drag_drop_client_);
 }
 
 TooltipController::~TooltipController() {
   if (tooltip_window_)
     tooltip_window_->RemoveObserver(this);
 }
 
 void TooltipController::UpdateTooltip(aura::Window* target) {
   // If tooltip is visible, we may want to hide it. If it is not, we are ok.
-  if (tooltip_window_ == target && tooltip_->IsVisible())
+  if (tooltip_window_ == target && GetTooltip()->IsVisible())
     UpdateIfRequired();
 
   // If we had stopped the tooltip timer for some reason, we must restart it if
   // there is a change in the tooltip.
   if (!tooltip_timer_.IsRunning()) {
     if (tooltip_window_ != target || (tooltip_window_ &&
         tooltip_text_ != aura::client::GetTooltipText(tooltip_window_))) {
       tooltip_timer_.Start(FROM_HERE,
           base::TimeDelta::FromMilliseconds(kTooltipTimeoutMs),
           this, &TooltipController::TooltipTimerFired);
@@ skipping 30 matching lines @@
           tooltip_window_->RemoveObserver(this);
         tooltip_window_ = target;
         tooltip_window_->AddObserver(this);
       }
       curr_mouse_loc_ = event->location();
       if (tooltip_timer_.IsRunning())
         tooltip_timer_.Reset();
 
       // We update the tooltip if it is visible, or if we force-hid it due to a
       // mouse press.
-      if (tooltip_->IsVisible() || tooltip_window_at_mouse_press_)
+      if (GetTooltip()->IsVisible() || tooltip_window_at_mouse_press_)
         UpdateIfRequired();
       break;
     case ui::ET_MOUSE_PRESSED:
       mouse_pressed_ = true;
       tooltip_window_at_mouse_press_ = target;
       if (target)
         tooltip_text_at_mouse_press_ = aura::client::GetTooltipText(target);
-      tooltip_->Hide();
+      GetTooltip()->Hide();
       break;
     case ui::ET_MOUSE_RELEASED:
       mouse_pressed_ = false;
       break;
     case ui::ET_MOUSE_CAPTURE_CHANGED:
       // We will not received a mouse release, so reset mouse pressed state.
       mouse_pressed_ = false;
     case ui::ET_MOUSEWHEEL:
       // Hide the tooltip for click, release, drag, wheel events.
-      if (tooltip_->IsVisible())
-        tooltip_->Hide();
+      if (GetTooltip()->IsVisible())
+        GetTooltip()->Hide();
       break;
     default:
       break;
   }
   return false;
 }
 
 ui::TouchStatus TooltipController::PreHandleTouchEvent(
     aura::Window* target,
     aura::TouchEvent* event) {
   // TODO(varunjain): need to properly implement tooltips for
   // touch events.
   // Hide the tooltip for touch events.
-  if (tooltip_->IsVisible())
-    tooltip_->Hide();
+  if (GetTooltip()->IsVisible())
+    GetTooltip()->Hide();
   if (tooltip_window_)
     tooltip_window_->RemoveObserver(this);
   tooltip_window_ = NULL;
   return ui::TOUCH_STATUS_UNKNOWN;
 }
 
 ui::GestureStatus TooltipController::PreHandleGestureEvent(
     aura::Window* target,
     aura::GestureEvent* event) {
   return ui::GESTURE_STATUS_UNKNOWN;
@@ skipping 88 matching lines @@
     }
   }
   *text = result;
 }
 
 void TooltipController::TooltipTimerFired() {
   UpdateIfRequired();
 }
 
 void TooltipController::TooltipShownTimerFired() {
-  tooltip_->Hide();
+  GetTooltip()->Hide();
 
   // Since the user presumably no longer needs the tooltip, we also stop the
   // tooltip timer so that tooltip does not pop back up. We will restart this
   // timer if the tooltip changes (see UpdateTooltip()).
   tooltip_timer_.Stop();
 }
 
 void TooltipController::UpdateIfRequired() {
   if (!tooltips_enabled_ || mouse_pressed_ || IsDragDropInProgress() ||
       !aura::Env::GetInstance()->cursor_manager()->cursor_visible()) {
-    tooltip_->Hide();
+    GetTooltip()->Hide();
     return;
   }
 
   string16 tooltip_text;
   if (tooltip_window_)
     tooltip_text = aura::client::GetTooltipText(tooltip_window_);
 
   // If the user pressed a mouse button. We will hide the tooltip and not show
   // it until there is a change in the tooltip.
   if (tooltip_window_at_mouse_press_) {
     if (tooltip_window_ == tooltip_window_at_mouse_press_ &&
         tooltip_text == tooltip_text_at_mouse_press_) {
-      tooltip_->Hide();
+      GetTooltip()->Hide();
       return;
     }
     tooltip_window_at_mouse_press_ = NULL;
   }
 
-  // We add the !tooltip_->IsVisible() below because when we come here from
+  // We add the !GetTooltip()->IsVisible() below because when we come here from
   // TooltipTimerFired(), the tooltip_text may not have changed but we still
   // want to update the tooltip because the timer has fired.
   // If we come here from UpdateTooltip(), we have already checked for tooltip
   // visibility and this check below will have no effect.
-  if (tooltip_text_ != tooltip_text || !tooltip_->IsVisible()) {
+  if (tooltip_text_ != tooltip_text || !GetTooltip()->IsVisible()) {
     tooltip_shown_timer_.Stop();
     tooltip_text_ = tooltip_text;
     if (tooltip_text_.empty()) {
-      tooltip_->Hide();
+      GetTooltip()->Hide();
     } else {
       string16 tooltip_text(tooltip_text_);
       gfx::Point widget_loc = curr_mouse_loc_;
       widget_loc = widget_loc.Add(
           tooltip_window_->GetBoundsInScreen().origin());
-      tooltip_->SetText(tooltip_text, widget_loc);
-      tooltip_->Show();
+      GetTooltip()->SetText(tooltip_text, widget_loc);
+      GetTooltip()->Show();
       tooltip_shown_timer_.Start(FROM_HERE,
           base::TimeDelta::FromMilliseconds(kTooltipShownTimeoutMs),
           this, &TooltipController::TooltipShownTimerFired);
     }
   }
 }
 
 bool TooltipController::IsTooltipVisible() {
-  return tooltip_->IsVisible();
+  return GetTooltip()->IsVisible();
 }
 
 bool TooltipController::IsDragDropInProgress() {
   return drag_drop_client_->IsDragDropInProgress();
 }
 
+TooltipController::Tooltip* TooltipController::GetTooltip() {
+  if (!tooltip_.get())
+    tooltip_.reset(new Tooltip);
+  return tooltip_.get();
+}
+
 }  // namespace internal
 }  // namespace ash