fix comma in GrAuditTrail json

src/gpu/GrAuditTrail.cpp

 /*
  * Copyright 2016 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "GrAuditTrail.h"
 
-void GrAuditTrail::JsonifyTArray(SkString* json, const char* name, const FrameArray& array) {
+void GrAuditTrail::JsonifyTArray(SkString* json, const char* name, const FrameArray& array,
+                                 bool addComma) {
     if (array.count()) {
+        if (addComma) {
+            json->appendf(",");
+        }
         json->appendf("\"%s\": [", name);
         for (int i = 0; i < array.count(); i++) {
             json->append(array[i]->toJson());
             if (i < array.count() - 1) {
                 json->append(",");
             }
         }
         json->append("]");
     }
 }
@@ skipping 61 matching lines @@
 };
 
 static SkString pretty_print_json(SkString json) {
     class PrettyPrintJson prettyPrintJson;
     return prettyPrintJson.prettify(json);
 }
 
 SkString GrAuditTrail::toJson(bool prettyPrint) const {
     SkString json;
     json.append("{");
-    JsonifyTArray(&json, "Stacks", fFrames);
+    JsonifyTArray(&json, "Stacks", fFrames, false);
     json.append("}");
 
     if (prettyPrint) {
         return pretty_print_json(json);
     } else {
         return json;
     }
 }
 
 SkString GrAuditTrail::Frame::toJson() const {
     SkString json;
     json.append("{");
-    json.appendf("\"Name\": \"%s\",", fName);
-    JsonifyTArray(&json, "Frames", fChildren);
+    json.appendf("\"Name\": \"%s\"", fName);
+    JsonifyTArray(&json, "Frames", fChildren, true);
     json.append("}");
     return json;
 }
 
 SkString GrAuditTrail::Batch::toJson() const {
     SkString json;
     json.append("{");
     json.appendf("\"Name\": \"%s\",", fName);
     json.append("\"Bounds\": {");
     json.appendf("\"Left\": %f,", fBounds.fLeft);
     json.appendf("\"Right\": %f,", fBounds.fRight);
     json.appendf("\"Top\": %f,", fBounds.fTop);
     json.appendf("\"Bottom\": %f", fBounds.fBottom);
     json.append("}");
     json.append("}");
     return json;
 }