mus: couple of changes for running tests with --mus

Tests configure an environment this is a bit different than real code,
so need some early outs.

BUG=786453
TEST=none

Change-Id: I44621add71a17821293949aa837c39c2b5394d9d
Reviewed-on: https://chromium-review.googlesource.com/807168Reviewed-by: Sadrul Chowdhury <sadrul@chromium.org>
Commit-Queue: Scott Violet <sky@chromium.org>
Cr-Commit-Position: refs/heads/master@{#521618}

content/browser/renderer_host/render_widget_host_view_base.cc

@@ -546,9 +546,11 @@ void RenderWidgetHostViewBase::EmbedChildFrameRendererWindowTreeClient(
 }
 
 void RenderWidgetHostViewBase::OnChildFrameDestroyed(int routing_id) {
-  DCHECK(render_widget_window_tree_client_);
   pending_embeds_.erase(routing_id);
-  render_widget_window_tree_client_->DestroyFrame(routing_id);
+  // Tests may not create |render_widget_window_tree_client_| (tests don't
+  // necessarily create RenderWidgetHostViewAura).
+  if (render_widget_window_tree_client_)
+    render_widget_window_tree_client_->DestroyFrame(routing_id);
 }
 #endif
 
@@ -569,8 +571,10 @@ void RenderWidgetHostViewBase::OnDidScheduleEmbed(
   if (iter == pending_embeds_.end() || iter->second != embed_id)
     return;
   pending_embeds_.erase(iter);
-  DCHECK(render_widget_window_tree_client_);
-  render_widget_window_tree_client_->Embed(routing_id, token);
+  // Tests may not create |render_widget_window_tree_client_| (tests don't
+  // necessarily create RenderWidgetHostViewAura).
+  if (render_widget_window_tree_client_)
+    render_widget_window_tree_client_->Embed(routing_id, token);
 }
 
 void RenderWidgetHostViewBase::ScheduleEmbed(

content/test/test_render_view_host.h

@@ -131,7 +131,11 @@ class TestRenderWidgetHostView : public RenderWidgetHostViewBase,
   void reset_did_change_compositor_frame_sink() {
     did_change_compositor_frame_sink_ = false;
   }
-
+#if defined(USE_AURA)
+  void ScheduleEmbed(ui::mojom::WindowTreeClientPtr client,
+                     base::OnceCallback<void(const base::UnguessableToken&)>
+                         callback) override {}
+#endif
   // viz::HostFrameSinkClient implementation.
   void OnFirstSurfaceActivation(const viz::SurfaceInfo& surface_info) override;
   void OnFrameTokenChanged(uint32_t frame_token) override;