add DidFailProvisionalLoad method

atom/browser/api/atom_api_web_contents.cc

@@ -197,6 +197,15 @@ void WebContents::DidFinishLoad(content::RenderFrameHost* render_frame_host,
     Emit("did-finish-load");
 }
 
+// this error occurs when host could not be found
+void WebContents::DidFailProvisionalLoad(
+    content::RenderFrameHost* render_frame_host,
+    const GURL& validated_url,
+    int error_code,
+    const base::string16& error_description) {
+  Emit("did-fail-load", error_code, error_description);
+}
+
 void WebContents::DidFailLoad(content::RenderFrameHost* render_frame_host,
                               const GURL& validated_url,
                               int error_code,

atom/browser/api/atom_api_web_contents.h

@@ -154,6 +154,10 @@ class WebContents : public mate::EventEmitter,
                    const GURL& validated_url,
                    int error_code,
                    const base::string16& error_description) override;
+  void DidFailProvisionalLoad(content::RenderFrameHost* render_frame_host,
+                              const GURL& validated_url,
+                              int error_code,
+                              const base::string16& error_description) override;
   void DidStartLoading(content::RenderViewHost* render_view_host) override;
   void DidStopLoading(content::RenderViewHost* render_view_host) override;
   void DidGetRedirectForResourceRequest(

spec/api-browser-window-spec.coffee

@@ -58,6 +58,11 @@ describe 'browser-window module', ->
         done()
       w.loadUrl 'about:blank'
 
+    it 'should emit did-fail-load event', (done) ->
+      w.webContents.on 'did-fail-load', ->
+        done()
+      w.loadUrl 'file://a.txt'
+
   describe 'BrowserWindow.show()', ->
     it 'should focus on window', ->
       return if isCI