In the config name, report the viewport, if one is provided.

Review URL: https://codereview.appspot.com/6942048

git-svn-id: http://skia.googlecode.com/svn/trunk@6804 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/tools/PictureRenderer.h b/tools/PictureRenderer.h
index eda89a0..99c58e0 100644
--- a/tools/PictureRenderer.h
+++ b/tools/PictureRenderer.h
@@ -130,6 +130,9 @@
      */
     SkString getConfigName() {
         SkString config = this->getConfigNameInternal();
+        if (!fViewport.isEmpty()) {
+            config.appendf("_viewport_%ix%i", fViewport.width(), fViewport.height());
+        }
         if (kRTree_BBoxHierarchyType == fBBoxHierarchyType) {
             config.append("_rtree");
         } else if (kTileGrid_BBoxHierarchyType == fBBoxHierarchyType) {