Test scaling for small images

dm/DMSrcSink.cpp

 /*
  * Copyright 2015 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "DMSrcSink.h"
 #include "SamplePipeControllers.h"
 #include "SkCodec.h"
@@ skipping 102 matching lines @@
         default:
             decodeInfo = decodeInfo.makeColorType(canvasColorType);
             break;
     }
 
     // Try to scale the image if it is desired
     SkISize size = codec->getScaledDimensions(fScale);
     if (size == decodeInfo.dimensions() && 1.0f != fScale) {
         return Error::Nonfatal("Test without scaling is uninteresting.");
     }
+
+    // Visually inspecting very small output images is not necessary.  We will
+    // cover these cases in unit testing.
+    if ((size.width() <= 10 || size.height() <= 10) && 1.0f != fScale) {
+        return Error::Nonfatal("Scaling very small images is uninteresting.");
+    }
     decodeInfo = decodeInfo.makeWH(size.width(), size.height());
 
     // Construct a color table for the decode if necessary
     SkAutoTUnref<SkColorTable> colorTable(NULL);
     SkPMColor* colorPtr = NULL;
     int* colorCountPtr = NULL;
     int maxColors = 256;
     if (kIndex_8_SkColorType == decodeInfo.colorType()) {
         SkPMColor colors[256];
         colorTable.reset(SkNEW_ARGS(SkColorTable, (colors, maxColors)));
@@ skipping 950 matching lines @@
             skr.visit<void>(i, drawsAsSingletonPictures);
         }
         SkAutoTUnref<SkPicture> macroPic(macroRec.endRecordingAsPicture());
 
         canvas->drawPicture(macroPic);
         return "";
     });
 }
 
 }  // namespace DM