Migrate HostZoomMap to live in StoragePartition.

chrome/browser/ui/zoom/zoom_controller.h

Index: chrome/browser/ui/zoom/zoom_controller.h
diff --git a/chrome/browser/ui/zoom/zoom_controller.h b/chrome/browser/ui/zoom/zoom_controller.h
index f456cbd6c201647a0ce01098be9324483e3bb080..2bab70070f9530985c644fea10c12c4ddc56ad24 100644
--- a/chrome/browser/ui/zoom/zoom_controller.h
+++ b/chrome/browser/ui/zoom/zoom_controller.h
@@ -70,6 +70,13 @@ class ZoomController : public content::WebContentsObserver,
 
   ZoomMode zoom_mode() const { return zoom_mode_; }
 
+  // Convenience method to get default zoom level. Implemented here for
+  // inlining.
+  double GetDefaultZoomLevel() const {
+    return content::HostZoomMap::GetForWebContents(web_contents())
+        ->GetDefaultZoomLevel();
+  }
+
   // Convenience method to quickly check if the tab's at default zoom.
   bool IsAtDefaultZoom() const;
 
@@ -142,7 +149,7 @@ class ZoomController : public content::WebContentsObserver,
   // Current zoom level.
   double zoom_level_;
 
-  // Used to access the default zoom level preference.
+  // Used to notify about changes in the default zoom level preference.
   DoublePrefMember default_zoom_level_;
 
   scoped_ptr<ZoomChangedEventData> event_data_;