Optimize color xforms when src and dst are matching

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 164 matching lines @@
 #if defined(SK_TEST_QCMS)
     else if (FLAGS_qcms) {
         // Set-up a row buffer to decode into before transforming to dst.
         fSrc.reset(fSrcInfo.minRowBytes());
     }
 #endif
 }
 
 void ColorCodecBench::onDraw(int n, SkCanvas*) {
 #if defined(SK_TEST_QCMS)
-    bool to8888 = FLAGS_srgb || FLAGS_qcms;
-#else
-    bool to8888 = FLAGS_srgb;
-#endif
-    if (to8888 && FLAGS_half) {
+    if (FLAGS_qcms && FLAGS_half) {
         SkDebugf("Error: Contradicting flags.\n");
         return;
     }
+#endif
 
     for (int i = 0; i < n; i++) {
 #if defined(SK_TEST_QCMS)
         if (FLAGS_qcms) {
             if (FLAGS_xform_only) {
                 this->xformOnlyQCMS();
             } else {
                 this->decodeAndXformQCMS();
             }
         } else
 #endif
         {
             if (FLAGS_xform_only) {
                 this->xformOnly();
             } else {
                 this->decodeAndXform();
             }
         }
     }
 }