Work around stack overflow

Review URL: https://codereview.appspot.com/7561043

git-svn-id: http://skia.googlecode.com/svn/trunk@8162 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/gm/modecolorfilters.cpp b/gm/modecolorfilters.cpp
index 3e1ccb8..9859faa 100644
--- a/gm/modecolorfilters.cpp
+++ b/gm/modecolorfilters.cpp
@@ -139,8 +139,10 @@
                         SkRect rect = SkRect::MakeXYWH(x * kRectWidth, y * kRectHeight,
                                                        SkIntToScalar(kRectWidth),
                                                        SkIntToScalar(kRectHeight));
+                        canvas->saveLayer(&rect, NULL);
                         canvas->drawRect(rect, bgPaint);
                         canvas->drawRect(rect, paint);
+                        canvas->restore();
                         ++idx;
                     }
                 }