Use SkASSERTResult to avoid unused local variables

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 205 matching lines @@
     fGesture.reset();
     fDefaultMatrix.reset();
     fDefaultMatrixInv.reset();
 
     if (fWindow->supportsContentRect() && fWindow->scaleContentToFit()) {
         const SkRect contentRect = fWindow->getContentRect();
         const SkISize slideSize = fSlides[fCurrentSlide]->getDimensions();
         const SkRect slideBounds = SkRect::MakeIWH(slideSize.width(), slideSize.height());
         if (contentRect.width() > 0 && contentRect.height() > 0) {
             fDefaultMatrix.setRectToRect(slideBounds, contentRect, SkMatrix::kStart_ScaleToFit);
-            bool inverted = fDefaultMatrix.invert(&fDefaultMatrixInv);
-            SkASSERT(inverted);
+            SkAssertResult(fDefaultMatrix.invert(&fDefaultMatrixInv));
         }
     }
 
     if (fWindow->supportsContentRect()) {
         const SkISize slideSize = fSlides[fCurrentSlide]->getDimensions();
         SkRect windowRect = fWindow->getContentRect();
         fDefaultMatrixInv.mapRect(&windowRect);
         fGesture.setTransLimit(SkRect::MakeWH(slideSize.width(), slideSize.height()), windowRect);
     }
 
@@ skipping 138 matching lines @@
     // Record measurements
     fMeasurements[fCurrentMeasurement++] = ms;
     fCurrentMeasurement &= (kMeasurementCount - 1);  // fast mod
     SkASSERT(fCurrentMeasurement < kMeasurementCount);
 
     fAnimTimer.updateTime();
     if (fSlides[fCurrentSlide]->animate(fAnimTimer) || fDisplayStats) {
         fWindow->inval();
     }
 }