Simplify OriginTrialContext and the way it validates tokens.

third_party/WebKit/Source/build/scripts/templates/OriginTrials.h.tmpl

 {% from 'macros.tmpl' import license %}
 {{license()}}
 
 #ifndef OriginTrials_h
 #define OriginTrials_h
 
 #include "core/CoreExport.h"
 #include "wtf/text/WTFString.h"
 
 namespace blink {
 
 class ExecutionContext;
 
 // A namespace with dynamic tests for experimental features which can be enabled through the
 // experimental framework via origin trial tokens.
 namespace OriginTrials {
     {% for feature in features %}
     {% if feature.origin_trial_feature_name %}
-    CORE_EXPORT bool {{feature.first_lowered_name}}Enabled(ExecutionContext*, String& errorMessage);
     CORE_EXPORT bool {{feature.first_lowered_name}}Enabled(ExecutionContext*);
     {% endif %}
     {% endfor %}
 } // namespace OriginTrials
 
 } // namespace blink
 
 #endif // OriginTrials_h