Forward MIME types to BrowserPlugin when a viewer is specified.

content/browser/loader/resource_dispatcher_host_impl.h

Index: content/browser/loader/resource_dispatcher_host_impl.h
diff --git a/content/browser/loader/resource_dispatcher_host_impl.h b/content/browser/loader/resource_dispatcher_host_impl.h
index 185fb0b075028941d540d9aa93df6314f71b1fa4..b1902973b9f0cecc9b0b4beb98cee9aa497f35af 100644
--- a/content/browser/loader/resource_dispatcher_host_impl.h
+++ b/content/browser/loader/resource_dispatcher_host_impl.h
@@ -58,6 +58,7 @@ class ResourceDispatcherHostDelegate;
 class ResourceMessageDelegate;
 class ResourceMessageFilter;
 class ResourceRequestInfoImpl;
+class StreamResourceHandler;
 class SaveFileManager;
 class WebContentsImpl;
 struct DownloadSaveInfo;
@@ -210,10 +211,13 @@ class CONTENT_EXPORT ResourceDispatcherHostImpl
       const DownloadUrlParameters::OnStartedCallback& started_cb);
 
   // Must be called after the ResourceRequestInfo has been created
-  // and associated with the request.
+  // and associated with the request.  If |payload| is set to a non-empty value,
+  // the value will be sent to the old resource handler instead of cancelling
+  // it, except on HTTP errors.
   scoped_ptr<ResourceHandler> MaybeInterceptAsStream(
       net::URLRequest* request,
-      ResourceResponse* response);
+      ResourceResponse* response,
+      std::string* payload);
 
   void ClearSSLClientAuthHandlerForRequest(net::URLRequest* request);