Implements the "Set to default" button on the zoom bubble.

chrome/browser/ui/views/location_bar/location_bar_view.cc

Index: chrome/browser/ui/views/location_bar/location_bar_view.cc
diff --git a/chrome/browser/ui/views/location_bar/location_bar_view.cc b/chrome/browser/ui/views/location_bar/location_bar_view.cc
index 4894ff6963de12d1432fc1bb02366a9ee34dc830..9e4e6d309484569e99298ce276aef7d1a2ee68e6 100644
--- a/chrome/browser/ui/views/location_bar/location_bar_view.cc
+++ b/chrome/browser/ui/views/location_bar/location_bar_view.cc
@@ -270,7 +270,11 @@ void LocationBarView::Init(views::View* popup_parent_view) {
     content_blocked_view->SetVisible(false);
   }
 
-  zoom_view_ = new ZoomView(model_);
+  // Create the zoom view. At this point, |delegate_| has not yet been assigned
+  // a TabContents, so calling GetTabContents() will just return NULL. Thus,
+  // |delegate_| itself is passed here, where it can be queried at a later time
+  // for the appropriate TabContents.
+  zoom_view_ = new ZoomView(model_, delegate_);
   AddChildView(zoom_view_);
 
   if (extensions::switch_utils::IsActionBoxEnabled()) {
@@ -515,7 +519,7 @@ void LocationBarView::SetZoomIconState(
 }
 
 void LocationBarView::ShowZoomBubble(int zoom_percent) {
-  ZoomBubbleView::ShowBubble(zoom_view_, zoom_percent, true);
+  ZoomBubbleView::ShowBubble(zoom_view_, GetTabContents(), true);
 }
 
 void LocationBarView::ShowChromeToMobileBubble() {