Revert of Remove about:srcdoc url conversion.

content/public/browser/web_contents_observer.h

Index: content/public/browser/web_contents_observer.h
diff --git a/content/public/browser/web_contents_observer.h b/content/public/browser/web_contents_observer.h
index b86bcb77c18851038d5d46f949424f7637c351a0..32a11dd9be3a867304de28a005030d553062d000 100644
--- a/content/public/browser/web_contents_observer.h
+++ b/content/public/browser/web_contents_observer.h
@@ -200,8 +200,9 @@
   // |render_frame_host| is the RenderFrameHost for which the provisional load
   // is happening.
   //
-  // Since the URL validation will strip error URLs, the boolean flag
-  // |is_error_page| will indicate that the not validated URL was an error page.
+  // Since the URL validation will strip error URLs, or srcdoc URLs, the boolean
+  // flags |is_error_page| and |is_iframe_srcdoc| will indicate that the not
+  // validated URL was either an error page or an iframe srcdoc.
   //
   // Note that during a cross-process navigation, several provisional loads
   // can be on-going in parallel.
@@ -210,7 +211,8 @@
   virtual void DidStartProvisionalLoadForFrame(
       RenderFrameHost* render_frame_host,
       const GURL& validated_url,
-      bool is_error_page) {}
+      bool is_error_page,
+      bool is_iframe_srcdoc) {}
 
   // This method is invoked when the provisional load was successfully
   // committed.