Bug 999239: Copy session history when recreating browser element for the remote -> non-remote transition. r=bz, r=felipe, sr=gavin

docshell/base/nsDocShell.cpp

@@ -9838,7 +9838,18 @@ nsDocShell::InternalLoad(nsIURI * aURI,
             return NS_OK;
         }
     }
-    
+
+    // Check if the webbrowser chrome wants the load to proceed; this can be
+    // used to cancel attempts to load URIs in the wrong process.
+    nsCOMPtr<nsIWebBrowserChrome3> browserChrome3 = do_GetInterface(mTreeOwner);
+    if (browserChrome3) {
+        bool shouldLoad;
+        rv = browserChrome3->ShouldLoadURI(this, aURI, aReferrer, &shouldLoad);
+        if (NS_SUCCEEDED(rv) && !shouldLoad) {
+            return NS_OK;
+        }
+    }
+
     // mContentViewer->PermitUnload can destroy |this| docShell, which
     // causes the next call of CanSavePresentation to crash. 
     // Hold onto |this| until we return, to prevent a crash from happening.