Caches the display names in MultiDisplayManager.

ash/system/chromeos/tray_display.cc

Index: ash/system/chromeos/tray_display.cc
diff --git a/ash/system/chromeos/tray_display.cc b/ash/system/chromeos/tray_display.cc
index 0e672d1d5a663fa52b87bcba1d99952219b0f8a4..d3c66a7af32fd8a8270240abbf5a829f9cce4c68 100644
--- a/ash/system/chromeos/tray_display.cc
+++ b/ash/system/chromeos/tray_display.cc
@@ -5,6 +5,7 @@
 #include "ash/system/chromeos/tray_display.h"
 
 #include "ash/display/display_controller.h"
+#include "ash/display/multi_display_manager.h"
 #include "ash/screen_ash.h"
 #include "ash/shell.h"
 #include "ash/system/tray/system_tray.h"
@@ -23,10 +24,6 @@
 #include "ui/views/controls/label.h"
 #include "ui/views/layout/box_layout.h"
 
-#if defined(USE_X11)
-#include "ui/base/x/x11_util.h"
-#endif
-
 namespace ash {
 namespace internal {
 
@@ -53,6 +50,9 @@ class DisplayView : public ash::internal::ActionableView {
   virtual ~DisplayView() {}
 
   void Update() {
+    MultiDisplayManager* display_manager = static_cast<MultiDisplayManager*>(
+        aura::Env::GetInstance()->display_manager());
+
     switch (Shell::GetInstance()->output_configurator()->output_state()) {
       case chromeos::STATE_INVALID:
       case chromeos::STATE_HEADLESS:
@@ -60,37 +60,25 @@ class DisplayView : public ash::internal::ActionableView {
         SetVisible(false);
         return;
       case chromeos::STATE_DUAL_MIRROR: {
-        // Simply assumes that the primary display appears first and the
-        // secondary display appears next in the list.
-        std::vector<std::string> display_names;
-#if defined(USE_X11)
-        std::vector<XID> output_ids;
-        ui::GetOutputDeviceHandles(&output_ids);
-        display_names = ui::GetDisplayNames(output_ids);
-#endif
-        if (display_names.size() > 1) {
-          label_->SetText(l10n_util::GetStringFUTF16(
-              IDS_ASH_STATUS_TRAY_DISPLAY_MIRRORING,
-              UTF8ToUTF16(display_names[1])));
-          SetVisible(true);
-        } else {
-          SetVisible(false);
-        }
+        std::vector<std::string> display_names =
+            display_manager->GetExternalDisplayNames();
+        string16 display_name = (!display_names.empty()) ?
+            UTF8ToUTF16(display_names[0]) :
+            l10n_util::GetStringUTF16(IDS_ASH_STATUS_TRAY_UNKNOWN_DISPLAY_NAME);
+        label_->SetText(l10n_util::GetStringFUTF16(
+            IDS_ASH_STATUS_TRAY_DISPLAY_MIRRORING, display_name));
+        SetVisible(true);
         return;
       }
       case chromeos::STATE_DUAL_PRIMARY_ONLY:
       case chromeos::STATE_DUAL_SECONDARY_ONLY: {
-        aura::DisplayManager* display_manager =
-            aura::Env::GetInstance()->display_manager();
-        if (display_manager->GetNumDisplays() > 1) {
-          label_->SetText(l10n_util::GetStringFUTF16(
-              IDS_ASH_STATUS_TRAY_DISPLAY_EXTENDED,
-              UTF8ToUTF16(display_manager->GetDisplayNameFor(
-                  ScreenAsh::GetSecondaryDisplay()))));
-          SetVisible(true);
-        } else {
-          SetVisible(false);
-        }
+        string16 display_name = (display_manager->GetNumDisplays() > 1) ?
+            UTF8ToUTF16(display_manager->GetDisplayNameFor(
+                ScreenAsh::GetSecondaryDisplay())) :
+            l10n_util::GetStringUTF16(IDS_ASH_STATUS_TRAY_UNKNOWN_DISPLAY_NAME);
+        label_->SetText(l10n_util::GetStringFUTF16(
+            IDS_ASH_STATUS_TRAY_DISPLAY_EXTENDED, display_name));
+        SetVisible(true);
         return;
       }
       default: