First pass at Rect Effect

src/gpu/SkGpuDevice.cpp

Index: src/gpu/SkGpuDevice.cpp
===================================================================
--- src/gpu/SkGpuDevice.cpp	(revision 8570)
+++ src/gpu/SkGpuDevice.cpp	(working copy)
@@ -671,9 +671,16 @@
     if (paint.getMaskFilter() || paint.getPathEffect()) {
         usePath = true;
     }
-    // until we aa rotated rects...
     if (!usePath && paint.isAntiAlias() && !fContext->getMatrix().rectStaysRect()) {
-        usePath = true;
+#ifdef SHADER_AA_FILL_RECT
+        if (doStroke) {
+#endif
+            usePath = true;
+#ifdef SHADER_AA_FILL_RECT
+        } else {
+            usePath = !fContext->getMatrix().preservesRightAngles();
+        }
+#endif
     }
     // small miter limit means right angles show bevel...
     if (SkPaint::kMiter_Join == paint.getStrokeJoin() &&