Quickly fix the Compile Problem of Unused kkImageColorXformMetaData

tools/viewer/Viewer.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 "Viewer.h"
 
 #include "GMSlide.h"
@@ skipping 357 matching lines @@
         canvas->clipRect(contentRect);
         canvas->translate(contentRect.fLeft, contentRect.fTop);
     }
 
     canvas->clear(SK_ColorWHITE);
     canvas->concat(fDefaultMatrix);
     canvas->concat(computeMatrix());
 
     if (inSplitScreen) {
         sk_sp<SkSurface> offscreenSurface = fWindow->getOffscreenSurface(true);
+        offscreenSurface->getCanvas()->getMetaData().setBool(kImageColorXformMetaData, true);
         fSlides[fCurrentSlide]->draw(offscreenSurface->getCanvas());
         sk_sp<SkImage> snapshot = offscreenSurface->makeImageSnapshot();
         canvas->drawImage(snapshot, 0, 0);
     } else {
         fSlides[fCurrentSlide]->draw(canvas);
     }
 
     canvas->restoreToCount(count);
 
     if (inSplitScreen) {
@@ skipping 201 matching lines @@
         bool newSplitScreen = stateValue.equals(kON);
         if (newSplitScreen != fSplitScreen) {
             fSplitScreen = newSplitScreen;
             fWindow->inval();
             updateUIState();
         }
     } else {
         SkDebugf("Unknown stateName: %s", stateName.c_str());
     }
 }