Add a PushClient getter in WebFrameTestProxy.

content/shell/renderer/test_runner/web_frame_test_proxy.h

Index: content/shell/renderer/test_runner/web_frame_test_proxy.h
diff --git a/content/shell/renderer/test_runner/web_frame_test_proxy.h b/content/shell/renderer/test_runner/web_frame_test_proxy.h
index 4c40ecc32371037272ea900ef74c6fa370fdf121..75b4948067d0bd4427832f8aff40a370d00eb84a 100644
--- a/content/shell/renderer/test_runner/web_frame_test_proxy.h
+++ b/content/shell/renderer/test_runner/web_frame_test_proxy.h
@@ -269,6 +269,10 @@ class WebFrameTestProxy : public Base {
     return base_proxy_->GetWebMIDIClient();
   }
 
+  virtual blink::WebPushClient* pushClient() {
+    return base_proxy_->GetWebPushClient();
+  }
+
   virtual bool willCheckAndDispatchMessageEvent(
       blink::WebLocalFrame* source_frame,
       blink::WebFrame* target_frame,