Add a FakeImeFeatureDelegate to the Linux client.

blimp/client/feature/render_widget_feature.h

Index: blimp/client/feature/render_widget_feature.h
diff --git a/blimp/client/feature/render_widget_feature.h b/blimp/client/feature/render_widget_feature.h
index e1af3a169af147834cc5e09743d5a77cc62e12b1..b18ec9f15b6b22e832eddf961f20745df15cad7b 100644
--- a/blimp/client/feature/render_widget_feature.h
+++ b/blimp/client/feature/render_widget_feature.h
@@ -89,11 +89,11 @@ class RenderWidgetFeature : public BlimpMessageProcessor {
   virtual void SetDelegate(int tab_id, RenderWidgetFeatureDelegate* delegate);
   virtual void RemoveDelegate(const int tab_id);
 
- private:
   // BlimpMessageProcessor implementation.
   void ProcessMessage(std::unique_ptr<BlimpMessage> message,
                       const net::CompletionCallback& callback) override;
 
+ private:
   void ProcessRenderWidgetMessage(
       RenderWidgetFeatureDelegate* delegate,
       const RenderWidgetMessage& message);