be sure to unlock the discardablememory before deleting it

src/lazy/SkDiscardablePixelRef.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 "SkDiscardablePixelRef.h"
 #include "SkDiscardableMemory.h"
 #include "SkImageGenerator.h"
@@ skipping 12 matching lines @@
     SkASSERT(fGenerator != NULL);
     SkASSERT(fSize > 0);
     SkASSERT(fRowBytes > 0);
     // The SkImageGenerator contract requires fGenerator to always
     // decode the same image on each call to getPixels().
     this->setImmutable();
     SkSafeRef(fDMFactory);
 }
 
 SkDiscardablePixelRef::~SkDiscardablePixelRef() {
+    if (this->isLocked()) {
+        fDiscardableMemory->unlock();
+    }
     SkDELETE(fDiscardableMemory);
     SkSafeUnref(fDMFactory);
     SkDELETE(fGenerator);
 }
 
 void* SkDiscardablePixelRef::onLockPixels(SkColorTable**) {
     if (fDiscardableMemory != NULL) {
         if (fDiscardableMemory->lock()) {
             return fDiscardableMemory->data();
         }
@@ skipping 37 matching lines @@
         return dst->allocPixels(NULL, NULL);
     }
     SkAutoTUnref<SkDiscardablePixelRef> ref(SkNEW_ARGS(SkDiscardablePixelRef,
                                                    (generator, info,
                                                     dst->getSize(),
                                                     dst->rowBytes(),
                                                     factory)));
     dst->setPixelRef(ref);
     return true;
 }