Fix debug-only crash installing app from app launcher.

chrome/browser/ui/browser.cc

 // Copyright 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.
 
 #include "chrome/browser/ui/browser.h"
 
 #if defined(OS_WIN)
 #include <windows.h>
 #include <shellapi.h>
 #endif  // defined(OS_WIN)
@@ skipping 1286 matching lines @@
 void Browser::ShowFirstRunBubble() {
   window()->GetLocationBar()->ShowFirstRunBubble();
 }
 
 void Browser::ShowDownload(content::DownloadItem* download) {
   if (!window())
     return;
 
   // If the download occurs in a new tab, and it's not a save page
   // download (started before initial navigation completed) close it.
+  // Avoid calling CloseContents if the tab is not in this browser's tab strip
+  // model; this can happen if the download was initiated by something internal
+  // to Chrome, such as by the app list.
   WebContents* source = download->GetWebContents();
   if (source && source->GetController().IsInitialNavigation() &&
-      tab_strip_model_->count() > 1 && !download->IsSavePackageDownload()) {
+      tab_strip_model_->count() > 1 &&
+      tab_strip_model_->GetIndexOfWebContents(source) !=
+          TabStripModel::kNoTab &&
+      !download->IsSavePackageDownload()) {
     CloseContents(source);
   }
 
   // Some (app downloads) are not supposed to appear on the shelf.
   if (!DownloadItemModel(download).ShouldShowInShelf())
     return;
 
   // GetDownloadShelf creates the download shelf if it was not yet created.
   DownloadShelf* shelf = window()->GetDownloadShelf();
   shelf->AddDownload(download);
@@ skipping 1175 matching lines @@
   if (contents && !allow_js_access) {
     contents->web_contents()->GetController().LoadURL(
         target_url,
         content::Referrer(),
         ui::PAGE_TRANSITION_LINK,
         std::string());  // No extra headers.
   }
 
   return contents != NULL;
 }