Cocoa: Media gallery dialog unit test

chrome/browser/ui/cocoa/extensions/media_galleries_dialog_cocoa.mm

Index: chrome/browser/ui/cocoa/extensions/media_galleries_dialog_cocoa.mm
diff --git a/chrome/browser/ui/cocoa/extensions/media_galleries_dialog_cocoa.mm b/chrome/browser/ui/cocoa/extensions/media_galleries_dialog_cocoa.mm
index a236a0ea6360cce108d4f0f41be6b75ed9521620..1db5b6ed24cae58680816b9dd2aa9e0184b04b1a 100644
--- a/chrome/browser/ui/cocoa/extensions/media_galleries_dialog_cocoa.mm
+++ b/chrome/browser/ui/cocoa/extensions/media_galleries_dialog_cocoa.mm
@@ -94,7 +94,9 @@ MediaGalleriesDialogCocoa::MediaGalleriesDialogCocoa(
       controller_->HasPermittedGalleries()];
 
   set_sheet(alert_);
-  window_ = new ConstrainedWindowMac(controller->tab_contents(), this);
+  // May be NULL during tests.
+  if (controller->tab_contents())
+    window_ = new ConstrainedWindowMac(controller->tab_contents(), this);
 }
 
 MediaGalleriesDialogCocoa::~MediaGalleriesDialogCocoa() {
@@ -125,10 +127,12 @@ void MediaGalleriesDialogCocoa::SheetDidEnd(NSInteger result) {
   switch (result) {
     case NSAlertFirstButtonReturn:
       accepted_ = true;
-      window_->CloseConstrainedWindow();
+      if (window_)
+        window_->CloseConstrainedWindow();
       break;
     case NSAlertSecondButtonReturn:
-      window_->CloseConstrainedWindow();
+      if (window_)
+        window_->CloseConstrainedWindow();
       break;
     default:
       NOTREACHED();