Add Dashing gpu effect for simple dashed lines

src/gpu/SkGpuDevice.cpp

Index: src/gpu/SkGpuDevice.cpp
diff --git a/src/gpu/SkGpuDevice.cpp b/src/gpu/SkGpuDevice.cpp
index 6543139c836ed02c0ddcf8e70caae14b8cab739a..30cae78311e3d30496e43d4dfed36f9f9e3e0490 100644
--- a/src/gpu/SkGpuDevice.cpp
+++ b/src/gpu/SkGpuDevice.cpp
@@ -8,6 +8,7 @@
 #include "SkGpuDevice.h"
 
 #include "effects/GrBicubicEffect.h"
+#include "effects/GrDashingEffect.h"
 #include "effects/GrTextureDomain.h"
 #include "effects/GrSimpleTextureEffect.h"
 
@@ -419,6 +420,12 @@ void SkGpuDevice::drawPoints(const SkDraw& draw, SkCanvas::PointMode mode,
         return;
     }
 
+    if (paint.getPathEffect() && 2 == count && SkCanvas::kLines_PointMode == mode) {
+        if (GrDashingEffect::DrawDashLine(pts, paint, this)) {
+            return;
+        }
+    }
+
     // we only handle hairlines and paints without path effects or mask filters,
     // else we let the SkDraw call our drawPath()
     if (width > 0 || paint.getPathEffect() || paint.getMaskFilter()) {