Fix SkDrawTextBlobCommand null blob crash

tools/debugger/SkDrawCommand.cpp

 /*
  * Copyright 2012 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkDrawCommand.h"
 
 #include "SkBlurMaskFilter.h"
@@ skipping 2795 matching lines @@
 
     SkAutoTDelete<SkString> runsStr(new SkString);
     fInfo.push(SkObjectParser::ScalarToString(x, "XPOS: "));
     fInfo.push(SkObjectParser::ScalarToString(y, "YPOS: "));
     fInfo.push(SkObjectParser::RectToString(fBlob->bounds(), "Bounds: "));
     fInfo.push(runsStr);
     fInfo.push(SkObjectParser::PaintToString(paint));
 
     unsigned runs = 0;
     SkPaint runPaint(paint);
-    SkTextBlobRunIterator iter(blob.get());
+    SkTextBlobRunIterator iter(fBlob.get());
     while (!iter.done()) {
         SkAutoTDelete<SkString> tmpStr(new SkString);
         tmpStr->printf("==== Run [%d] ====", runs++);
         fInfo.push(tmpStr.release());
 
         fInfo.push(SkObjectParser::IntToString(iter.glyphCount(), "GlyphCount: "));
         tmpStr.reset(new SkString("GlyphPositioning: "));
         tmpStr->append(gPositioningLabels[iter.positioning()]);
         fInfo.push(tmpStr.release());
 
@@ skipping 720 matching lines @@
 SkTranslateZCommand* SkTranslateZCommand::fromJSON(Json::Value& command,
                                        UrlDataManager& urlDataManager) {
     SkScalar z;
 #ifdef SK_EXPERIMENTAL_SHADOWING
     extract_json_scalar(command[SKDEBUGCANVAS_ATTRIBUTE_DRAWDEPTHTRANS], &z);
 #else
     z = 0;
 #endif
     return new SkTranslateZCommand(z);
 }