Merge pull request #5192 from nnethercote/empty-setGState

Ignore setGState no-ops.

src/core/evaluator.js

@@ -412,7 +412,7 @@ var PartialEvaluator = (function PartialEvaluatorClosure() {
 
             break;
           // Only generate info log messages for the following since
-          // they are unlikey to have a big impact on the rendering.
+          // they are unlikely to have a big impact on the rendering.
           case 'OP':
           case 'op':
           case 'OPM':
@@ -446,7 +446,9 @@ var PartialEvaluator = (function PartialEvaluatorClosure() {
         setGStateForKey(gStateObj, key, value);
       }
       return promise.then(function () {
+        if (gStateObj.length >= 0) {
           operatorList.addOp(OPS.setGState, [gStateObj]);
+        }
       });
     },