prune down content_dll change to just the CONTENT_EXPORTS

content/browser/renderer_host/render_view_host_observer.h

Index: content/browser/renderer_host/render_view_host_observer.h
diff --git a/content/browser/renderer_host/render_view_host_observer.h b/content/browser/renderer_host/render_view_host_observer.h
index 2c3b749229542da6ec3e241faee074aec0281180..21e0c7011511c26473b22d09875d94fce63e8152 100644
--- a/content/browser/renderer_host/render_view_host_observer.h
+++ b/content/browser/renderer_host/render_view_host_observer.h
@@ -6,14 +6,15 @@
 #define CONTENT_BROWSER_RENDERER_HOST_RENDER_VIEW_HOST_OBSERVER_H_
 
 #include "ipc/ipc_channel.h"
+#include "content/common/content_export.h"
 
 class RenderViewHost;
 struct ViewMsg_Navigate_Params;
 
 // An observer API implemented by classes which want to filter IPC messages from
 // RenderViewHost.
-class RenderViewHostObserver : public IPC::Channel::Listener,
-                               public IPC::Message::Sender {
+class CONTENT_EXPORT RenderViewHostObserver : public IPC::Channel::Listener,
+                                              public IPC::Message::Sender {
  public:
 
  protected: