Fix two leaks & improve leak tracking

src/doc/SkDocument.cpp

 /*
  * Copyright 2013 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkDocument.h"
 #include "SkStream.h"
 
+SK_DEFINE_INST_COUNT(SkDocument)
+
 SkDocument::SkDocument(SkWStream* stream, void (*doneProc)(SkWStream*)) {
     fStream = stream;   // we do not own this object.
     fDoneProc = doneProc;
     fState = kBetweenPages_State;
 }
 
 SkDocument::~SkDocument() {
     this->close();
 }
 
@@ skipping 52 matching lines @@
                 fStream = NULL;
                 return;
             case kInPage_State:
                 this->endPage();
                 break;
             case kClosed_State:
                 return;
         }
     }
 }