re-emable u64 gm

gm/xferu64.cpp

 /*
  * Copyright 2016 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "gm.h"
 #include "SkCanvas.h"
 #include "SkImageInfo.h"
@@ skipping 78 matching lines @@
     }
 
     SkAutoTUnref<SkImage> image(new_u64_image(bm, u64_flags));
     canvas->drawImage(image, r.left(), r.top(), nullptr);
 }
 
 /*
  *  Test SkXfer4fProcs directly for src-over, comparing them to current SkColor blits.
  */
 DEF_SIMPLE_GM(xfer_u64_srcover, canvas, 580, 760) {
-    return; // disable for now, until we understand the failures on Nexus 5 etc.
-
     const int IW = 50;
     const SkScalar W = IW;
     const SkScalar H = 100;
 
     const int32_t flags[] = {
         -1,                                 // normal
         0,                                  // U16 components
         SkXfermode::kDstIsFloat16_U64Flag,  // F16 components
     };
     const SkColor colors[] = {
@@ skipping 31 matching lines @@
                 }
                 canvas->translate(W + 20, 0);
             }
             canvas->restore();
             canvas->translate(0, H + 20);
         }
         canvas->restore();
         canvas->translate(0, (H + 20) * SK_ARRAY_COUNT(flags) + 20);
     }
 }