fixed off-by-one error in skiaserve /cmd

tools/skiaserve/skiaserve.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 "GrCaps.h"
 #include "GrContextFactory.h"
 #include "SkCanvas.h"
@@ skipping 215 matching lines @@
         SkStrSplit(url, "/", &commands);
 
         if (!request->fPicture.get() || commands.count() > 3) {
             return MHD_NO;
         }
 
         // /cmd or /cmd/N
         if (0 == strcmp(method, MHD_HTTP_METHOD_GET)) {
             int n;
             if (commands.count() == 1) {
-                n = request->fDebugCanvas->getSize() - 1;
+                n = request->fDebugCanvas->getSize();
             } else {
                 sscanf(commands[1].c_str(), "%d", &n);
             }
             return SendJSON(connection, request->fDebugCanvas, &request->fUrlDataManager, n);
         }
 
         // /cmd/N, for now only delete supported
         if (commands.count() == 2 && 0 == strcmp(method, MHD_HTTP_METHOD_DELETE)) {
             int n;
             sscanf(commands[1].c_str(), "%d", &n);
@@ skipping 316 matching lines @@
     MHD_stop_daemon(daemon);
     return 0;
 }
 
 #if !defined SK_BUILD_FOR_IOS
 int main(int argc, char** argv) {
     SkCommandLineFlags::Parse(argc, argv);
     return skiaserve_main();
 }
 #endif