Create Tooltip object lazily so that it gets proper drop shadow

ash/tooltips/tooltip_controller.cc

Index: ash/tooltips/tooltip_controller.cc
diff --git a/ash/tooltips/tooltip_controller.cc b/ash/tooltips/tooltip_controller.cc
index df4f86291ed1a90c87e4690896d0116276292481..937ebc7a75008745362b71dc9d4f2a1af7709e8b 100644
--- a/ash/tooltips/tooltip_controller.cc
+++ b/ash/tooltips/tooltip_controller.cc
@@ -185,7 +185,6 @@ TooltipController::TooltipController(
       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),
@@ -200,7 +199,7 @@ TooltipController::~TooltipController() {
 
 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
@@ -251,7 +250,7 @@ bool TooltipController::PreHandleMouseEvent(aura::Window* target,
 
       // 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:
@@ -259,7 +258,7 @@ bool TooltipController::PreHandleMouseEvent(aura::Window* target,
       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;
@@ -269,8 +268,8 @@ bool TooltipController::PreHandleMouseEvent(aura::Window* target,
       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;
@@ -284,8 +283,8 @@ ui::TouchStatus TooltipController::PreHandleTouchEvent(
   // 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;
@@ -394,7 +393,7 @@ void TooltipController::TooltipTimerFired() {
 }
 
 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
@@ -405,7 +404,7 @@ void TooltipController::TooltipShownTimerFired() {
 void TooltipController::UpdateIfRequired() {
   if (!tooltips_enabled_ || mouse_pressed_ || IsDragDropInProgress() ||
       !aura::Env::GetInstance()->cursor_manager()->cursor_visible()) {
-    tooltip_->Hide();
+    GetTooltip()->Hide();
     return;
   }
 
@@ -418,29 +417,29 @@ void TooltipController::UpdateIfRequired() {
   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);
@@ -449,12 +448,18 @@ void TooltipController::UpdateIfRequired() {
 }
 
 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