linux-aura: Restore middle-click on new-tab button behaviour.

chrome/browser/ui/browser_tab_strip_model_delegate.cc

Index: chrome/browser/ui/browser_tab_strip_model_delegate.cc
diff --git a/chrome/browser/ui/browser_tab_strip_model_delegate.cc b/chrome/browser/ui/browser_tab_strip_model_delegate.cc
index 43a8d51965ad90f840c189528b2c6cb151cf71fd..2107cdcebd706ae7abb40e0639e1f2d3dcb0e409 100644
--- a/chrome/browser/ui/browser_tab_strip_model_delegate.cc
+++ b/chrome/browser/ui/browser_tab_strip_model_delegate.cc
@@ -43,6 +43,15 @@ void BrowserTabStripModelDelegate::AddBlankTabAt(int index, bool foreground) {
   chrome::AddBlankTabAt(browser_, index, foreground);
 }
 
+void BrowserTabStripModelDelegate::AddURLTabAt(const GURL& url,
+                                               int index,
+                                               bool foreground) {
+  NavigateParams params(browser_, url, content::PAGE_TRANSITION_TYPED);
+  params.disposition = foreground ? NEW_FOREGROUND_TAB : NEW_BACKGROUND_TAB;
+  params.tabstrip_index = index;
+  Navigate(&params);
+}
+
 Browser* BrowserTabStripModelDelegate::CreateNewStripWithContents(
     const std::vector<NewStripContents>& contentses,
     const gfx::Rect& window_bounds,