Show download interrupt reason in a tooltip

chrome/browser/ui/cocoa/download/download_item_controller.mm

 // 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.
 
 #import "chrome/browser/ui/cocoa/download/download_item_controller.h"
 
 #include "base/mac/bundle_locations.h"
 #include "base/mac/mac_util.h"
 #include "base/metrics/histogram.h"
 #include "base/string16.h"
@@ skipping 227 matching lines @@
     return [progressView_ frame].size;
   DCHECK_EQ(kDangerous, state_);
   return [dangerousDownloadView_ frame].size;
 }
 
 - (DownloadItem*)download {
   return bridge_->download_model()->download();
 }
 
 - (void)updateToolTip {
-  string16 elidedFilename = ui::ElideFilename(
+  string16 tooltip_text = ui::ElideFilename(
       [self download]->GetFileNameToReportUser(), *font_, kToolTipMaxWidth);
-  [progressView_ setToolTip:base::SysUTF16ToNSString(elidedFilename)];
+
+  if ([self download]->GetState() == content::DownloadItem::INTERRUPTED) {
+    content::DownloadInterruptReason reason = [self download]->GetLastReason();
+    DCHECK_NE(0, reason);
+
+    // Add the status on another line.
+    tooltip_text += ASCIIToUTF16("\n");
+    tooltip_text += DownloadItemModel::InterruptReasonStatusMessage(reason);
+  }
+
+  [progressView_ setToolTip:base::SysUTF16ToNSString(tooltip_text)];
 }
 
 - (void)clearDangerousMode {
   [self setState:kNormal];
   // The state change hide the dangerouse download view and is now showing the
   // download progress view.  This means the view is likely to be a different
   // size, so trigger a shelf layout to fix up spacing.
   [shelf_ layoutItems];
 }
 
@@ skipping 106 matching lines @@
     [sender setTitle:l10n_util::GetNSStringWithFixup(
         IDS_DOWNLOAD_MENU_PAUSE_ITEM)];
   } else {
     [sender setTitle:l10n_util::GetNSStringWithFixup(
         IDS_DOWNLOAD_MENU_RESUME_ITEM)];
   }
   menuBridge_->ExecuteCommand(DownloadShelfContextMenuMac::TOGGLE_PAUSE);
 }
 
 @end