merge with changes for GPU backend



git-svn-id: http://skia.googlecode.com/svn/trunk@637 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/samplecode/SampleLayers.cpp b/samplecode/SampleLayers.cpp
index ae8bd33..f1e8dd8 100644
--- a/samplecode/SampleLayers.cpp
+++ b/samplecode/SampleLayers.cpp
@@ -161,7 +161,7 @@
             SkPaint p;
             canvas->saveLayer(&r, &p);
             canvas->drawColor(0xFFFF0000);
-            p.setAlpha(1);  // or 0
+            p.setAlpha(0);  // or 0
             p.setXfermodeMode(SkXfermode::kSrc_Mode);
             canvas->drawOval(r, p);
             canvas->restore();