lock pixels in image when bitmap is immutable and not-lazy

tests/ImageTest.cpp

 /*
  * Copyright 2015 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkCanvas.h"
 #include "SkData.h"
 #include "SkDevice.h"
@@ skipping 227 matching lines @@
     for (size_t i = 0; i < SK_ARRAY_COUNT(rec); ++i) {
         SkBitmap bm;
         rec[i].fMakeProc(&bm);
 
         SkAutoTUnref<SkImage> image(SkImage::NewFromBitmap(bm));
         SkPixmap pmap;
 
         const bool sharedID = (image->uniqueID() == bm.getGenerationID());
         REPORTER_ASSERT(reporter, sharedID == rec[i].fExpectSharedID);
 
-#if 0   // TODO: fix so that peek will succeed in the immutable case
         const bool peekSuccess = image->peekPixels(&pmap);
         REPORTER_ASSERT(reporter, peekSuccess == rec[i].fExpectPeekSuccess);
-#endif
     }
 }