Make SetupMainWorldOverrides/isolated_world pure virtual.

Also implement stubs in AtomSandboxedRendererClient.

atom/renderer/atom_renderer_client.h

@@ -23,8 +23,6 @@ class AtomRendererClient : public RendererClientBase {
   // Get the context that the Electron API is running in.
   v8::Local<v8::Context> GetContext(
       blink::WebFrame* frame, v8::Isolate* isolate);
-  void SetupMainWorldOverrides(v8::Handle<v8::Context> context);
-  bool isolated_world() { return isolated_world_; }
 
   // atom::RendererClientBase:
   void DidCreateScriptContext(
@@ -33,6 +31,8 @@ class AtomRendererClient : public RendererClientBase {
   void WillReleaseScriptContext(
       v8::Handle<v8::Context> context,
       content::RenderFrame* render_frame) override;
+  void SetupMainWorldOverrides(v8::Handle<v8::Context> context) override;
+  bool isolated_world() override { return isolated_world_; }
 
  private:
   enum NodeIntegration {

atom/renderer/atom_sandboxed_renderer_client.h

@@ -26,6 +26,8 @@ class AtomSandboxedRendererClient : public RendererClientBase {
   void WillReleaseScriptContext(
       v8::Handle<v8::Context> context,
       content::RenderFrame* render_frame) override;
+  void SetupMainWorldOverrides(v8::Handle<v8::Context> context) override { }
+  bool isolated_world() override { return false; }
   // content::ContentRendererClient:
   void RenderFrameCreated(content::RenderFrame*) override;
   void RenderViewCreated(content::RenderView*) override;

atom/renderer/renderer_client_base.h

@@ -24,6 +24,8 @@ class RendererClientBase : public content::ContentRendererClient {
   virtual void WillReleaseScriptContext(
       v8::Handle<v8::Context> context, content::RenderFrame* render_frame) = 0;
   virtual void DidClearWindowObject(content::RenderFrame* render_frame);
+  virtual void SetupMainWorldOverrides(v8::Handle<v8::Context> context) = 0;
+  virtual bool isolated_world() = 0;
 
  protected:
   void AddRenderBindings(v8::Isolate* isolate,