Add OnDisplayMetricsChanged in DisplayObserver.

chrome/browser/ui/ash/launcher/browser_status_monitor.cc

Index: chrome/browser/ui/ash/launcher/browser_status_monitor.cc
diff --git a/chrome/browser/ui/ash/launcher/browser_status_monitor.cc b/chrome/browser/ui/ash/launcher/browser_status_monitor.cc
index 36b1935a14f8091ef9a8a5fffa3946577e9d3842..a2a296f394e6813b05475dd11523fdc06268ce48 100644
--- a/chrome/browser/ui/ash/launcher/browser_status_monitor.cc
+++ b/chrome/browser/ui/ash/launcher/browser_status_monitor.cc
@@ -224,11 +224,6 @@ void BrowserStatusMonitor::OnBrowserRemoved(Browser* browser) {
   UpdateBrowserItemState();
 }
 
-void BrowserStatusMonitor::OnDisplayBoundsChanged(
-    const gfx::Display& display) {
-  // Do nothing here.
-}
-
 void BrowserStatusMonitor::OnDisplayAdded(const gfx::Display& new_display) {
   // Add a new RootWindow and its ActivationClient to observed list.
   aura::Window* root_window = ash::Shell::GetInstance()->
@@ -249,6 +244,11 @@ void BrowserStatusMonitor::OnDisplayRemoved(const gfx::Display& old_display) {
   // Do nothing here.
 }
 
+void BrowserStatusMonitor::OnDisplayMetricsChanged(const gfx::Display&,
+                                                   uint32_t) {
+  // Do nothing here.
+}
+
 void BrowserStatusMonitor::ActiveTabChanged(content::WebContents* old_contents,
                                             content::WebContents* new_contents,
                                             int index,