Add GL strings to CastSysInfo interface and use to configure GPU

chromecast/base/cast_sys_info_dummy.h

Index: chromecast/base/cast_sys_info_dummy.h
diff --git a/chromecast/base/cast_sys_info_dummy.h b/chromecast/base/cast_sys_info_dummy.h
index 0b804a2d50a22a309ab685a624c050113eb7f254..89a8b8beeb96659805d90b9871cfeedae46f2285 100644
--- a/chromecast/base/cast_sys_info_dummy.h
+++ b/chromecast/base/cast_sys_info_dummy.h
@@ -29,6 +29,9 @@ class CastSysInfoDummy : public CastSysInfo {
   std::string GetFactoryLocale(std::string* second_locale) override;
   std::string GetWifiInterface() override;
   std::string GetApInterface() override;
+  std::string GetGlVendor() override;
+  std::string GetGlRenderer() override;
+  std::string GetGlVersion() override;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(CastSysInfoDummy);