[content] Use RFHT::SimulateLoadingCompleted in NavigationSimulator

R=clamy@chromium.org,ahemery@chromium.org
BUG=1011770

Change-Id: Ic4935b2f74d2fffe9ea6df0db0f796e6d4fe6f1c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1836091
Commit-Queue: Alexander Timin <altimin@chromium.org>
Reviewed-by: Camille Lamy <clamy@chromium.org>
Cr-Commit-Position: refs/heads/master@{#704382}

content/test/navigation_simulator_impl.cc

@@ -1341,8 +1341,7 @@ void NavigationSimulatorImpl::SetKeepLoading(bool keep_loading) {
 
 void NavigationSimulatorImpl::StopLoading() {
   CHECK(render_frame_host_);
-  render_frame_host_->OnMessageReceived(
-      FrameHostMsg_DidStopLoading(render_frame_host_->GetRoutingID()));
+  render_frame_host_->SimulateLoadingCompleted();
 }
 
 void NavigationSimulatorImpl::FailLoading(

content/test/test_render_frame_host.cc

@@ -693,4 +693,8 @@ TestRenderFrameHost::CreateStubBrowserInterfaceBrokerReceiver() {
       .InitWithNewPipeAndPassReceiver();
 }
 
+void TestRenderFrameHost::SimulateLoadingCompleted() {
+  OnDidStopLoading();
+}
+
 }  // namespace content

content/test/test_render_frame_host.h

@@ -207,6 +207,10 @@ class TestRenderFrameHost : public RenderFrameHostImpl,
     return navigation_requests_;
   }
 
+  // Simulates RenderFrameHost finishing loading and dispatching all relevant
+  // callbacks.
+  void SimulateLoadingCompleted();
+
  protected:
   void SendCommitNavigation(
       mojom::NavigationClient* navigation_client,