prune down content_dll change to just the CONTENT_EXPORTS

content/browser/host_zoom_map.h

Index: content/browser/host_zoom_map.h
diff --git a/content/browser/host_zoom_map.h b/content/browser/host_zoom_map.h
index fd17c77133d64dd64a7448f28e3dc6877c87671b..a365d53ddce095c5b52764a70bd73ebbf2b994a4 100644
--- a/content/browser/host_zoom_map.h
+++ b/content/browser/host_zoom_map.h
@@ -17,6 +17,7 @@
 #include "base/memory/ref_counted.h"
 #include "base/synchronization/lock.h"
 #include "content/browser/browser_thread.h"
+#include "content/common/content_export.h"
 #include "content/common/notification_observer.h"
 #include "content/common/notification_registrar.h"
 
@@ -24,10 +25,10 @@ class GURL;
 
 // HostZoomMap needs to be deleted on the UI thread because it listens
 // to notifications on there (and holds a NotificationRegistrar).
-class HostZoomMap :
-    public NotificationObserver,
-    public base::RefCountedThreadSafe<HostZoomMap,
-                                      BrowserThread::DeleteOnUIThread> {
+class CONTENT_EXPORT HostZoomMap
+    : public NotificationObserver,
+      public base::RefCountedThreadSafe<HostZoomMap,
+                                        BrowserThread::DeleteOnUIThread> {
  public:
   HostZoomMap();
 
@@ -73,6 +74,8 @@ class HostZoomMap :
   void set_default_zoom_level(double level) { default_zoom_level_ = level; }
 
  private:
+  friend base::RefCountedThreadSafe<HostZoomMap,
+                                    BrowserThread::DeleteOnUIThread>;
   friend struct BrowserThread::DeleteOnThread<BrowserThread::UI>;
   friend class DeleteTask<HostZoomMap>;