make allocPixels throw on failure

src/images/SkImageDecoder.cpp

 /*
  * Copyright 2006 The Android Open Source Project
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 
 #include "SkImageDecoder.h"
 #include "SkBitmap.h"
@@ skipping 115 matching lines @@
         return true;
     }
     chooser->begin(1);
     chooser->inspect(0, SkColorTypeToBitmapConfig(colorType), width, height);
     return chooser->choose() == 0;
 }
 #endif
 
 bool SkImageDecoder::allocPixelRef(SkBitmap* bitmap,
                                    SkColorTable* ctable) const {
-    return bitmap->allocPixels(fAllocator, ctable);
+    return bitmap->tryAllocPixels(fAllocator, ctable);
 }
 
 ///////////////////////////////////////////////////////////////////////////////
 
 SkColorType SkImageDecoder::getPrefColorType(SrcDepth srcDepth, bool srcHasAlpha) const {
     SkColorType ct = fDefaultPref;
     if (fPreserveSrcDepth) {
         switch (srcDepth) {
             case kIndex_SrcDepth:
                 ct = kIndex_8_SkColorType;
@@ skipping 131 matching lines @@
             if (kUnknown_Format == *format) {
                 if (stream->rewind()) {
                     *format = GetStreamFormat(stream);
                 }
             }
         }
         delete codec;
     }
     return success;
 }