Add error description to the DidFailProvisionalLoad callback.

content/public/renderer/content_renderer_client.h

Index: content/public/renderer/content_renderer_client.h
diff --git a/content/public/renderer/content_renderer_client.h b/content/public/renderer/content_renderer_client.h
index 9855ee0eef208c26fbaa8c48c5876be00eca6713..67b850239232e9be0e9f3a10f720e1960a89fe39 100644
--- a/content/public/renderer/content_renderer_client.h
+++ b/content/public/renderer/content_renderer_client.h
@@ -69,10 +69,19 @@ class ContentRendererClient {
   virtual bool HasErrorPage(int http_status_code,
                             std::string* error_domain) = 0;
 
-  // Returns the html to display when a navigation error occurs.
-  virtual std::string GetNavigationErrorHtml(
+  // Returns the information to display when a navigation error occurs.
+  // If |error_html| is not null then it may be set to a HTML page containing
+  // the details of the error and maybe links to more info.
+  // If |error_description| is not null it may be set to contain a brief
+  // message describing the error that has occurred.
+  // Either of the out parameters may be not written to in certain cases
+  // (lack of information on the error code) so the caller should take care to
+  // initialize the string values with safe defaults before the call.
+  virtual void GetNavigationErrorStrings(
       const WebKit::WebURLRequest& failed_request,
-      const WebKit::WebURLError& error) = 0;
+      const WebKit::WebURLError& error,
+      std::string* error_html,
+      string16* error_description) = 0;
 
   // Returns true if the renderer process should schedule the idle handler when
   // all widgets are hidden.