call notifyPixelsChanged() when the pages are flipped in pageflippixelref
update samples



git-svn-id: http://skia.googlecode.com/svn/trunk@192 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/samplecode/SamplePageFlip.cpp b/samplecode/SamplePageFlip.cpp
index 6b1adfd..ed4d340 100644
--- a/samplecode/SamplePageFlip.cpp
+++ b/samplecode/SamplePageFlip.cpp
@@ -44,7 +44,7 @@
     SkPaint paint;
     
     paint.setAntiAlias(true);
-    paint.setColor(reinterpret_cast<SkColor>(ref) | (0xFF << 24));
+    paint.setColor(SK_ColorRED);
     
     SkRect oval;
     oval.setEmpty();