Add widevine third party

Add 2 new command options to use widevine:
- widevine-cdm-path: Path to widevine plugin
- widevine-cdm-version: Version of the widevine plugin

atom/renderer/atom_renderer_client.h

@@ -6,6 +6,7 @@
 #define ATOM_RENDERER_ATOM_RENDERER_CLIENT_H_
 
 #include <string>
+#include <vector>
 
 #include "content/public/renderer/content_renderer_client.h"
 #include "content/public/renderer/render_process_observer.h"
@@ -58,7 +59,7 @@ class AtomRendererClient : public content::ContentRendererClient,
   bool ShouldOverridePageVisibilityState(
       const content::RenderFrame* render_frame,
       blink::WebPageVisibilityState* override_state) override;
-
+  void AddKeySystems(std::vector<media::KeySystemInfo>* key_systems) override;
   void EnableWebRuntimeFeatures();
 
   scoped_ptr<NodeBindings> node_bindings_;