Reduce overhead for linear color xforms

bench/ColorCodecBench.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 "ColorCodecBench.h"
 #include "Resources.h"
 #include "SkCodec.h"
@@ skipping 143 matching lines @@
         qcms_profile_precache_output_transform(fDstSpaceQCMS);
     } else
 #endif
     {
         fDstSpace = FLAGS_srgb ? SkColorSpace::NewNamed(SkColorSpace::kSRGB_Named) :
                                  SkColorSpace::NewICC(dstData->data(), dstData->size());
         SkASSERT(fDstSpace);
     }
 
     fSrcInfo = codec->getInfo().makeColorType(kRGBA_8888_SkColorType);
+    fDstInfo = fSrcInfo;
 
     if (FLAGS_half) {
         fDstInfo = fDstInfo.makeColorType(kRGBA_F16_SkColorType);
         fDstSpace = fDstSpace->makeLinearGamma();
     }
 
-    fDstInfo = fSrcInfo.makeColorSpace(fDstSpace);
+    fDstInfo = fDstInfo.makeColorSpace(fDstSpace);
 
     fDst.reset(fDstInfo.getSafeSize(fDstInfo.minRowBytes()));
 
     if (FLAGS_xform_only) {
         fSrc.reset(fSrcInfo.getSafeSize(fSrcInfo.minRowBytes()));
         codec->getPixels(fSrcInfo, fSrc.get(), fSrcInfo.minRowBytes());
     }
 #if defined(SK_TEST_QCMS)
     else if (FLAGS_qcms) {
         // Set-up a row buffer to decode into before transforming to dst.
@@ skipping 22 matching lines @@
 #endif
         {
             if (FLAGS_xform_only) {
                 this->xformOnly();
             } else {
                 this->decodeAndXform();
             }
         }
     }
 }