Fix up constructor naming style for MaskFilter and ColorFilter.

R=abarth@chromium.org

Review URL: https://codereview.chromium.org/1179913002.

examples/game/lib/sprite.dart

@@ -55,7 +55,7 @@ class Sprite extends NodeWithSize {
       Paint paint = new Paint();
       paint.setARGB((255.0*_opacity).toInt(), 255, 255, 255);
       if (colorOverlay != null) {
-        paint.setColorFilter(new ColorFilter.Mode(colorOverlay, TransferMode.srcATopMode));
+        paint.setColorFilter(new ColorFilter.mode(colorOverlay, TransferMode.srcATopMode));
       }
       if (transferMode != null) {
         paint.setTransferMode(transferMode);

examples/raw/painting.sky

@@ -55,10 +55,10 @@ void main() {
             (Paint layerPaint) {
           layerPaint.color = const Color.fromARGB(128, 255, 255, 0);
           layerPaint.setColorFilter(
-              new ColorFilter.Mode(const Color.fromARGB(128, 0, 0, 255),
+              new ColorFilter.mode(const Color.fromARGB(128, 0, 0, 255),
                                    TransferMode.srcInMode));
           layerPaint.setMaskFilter(
-              new MaskFilter.Blur(BlurStyle.normal, 3.0, highQuality: true));
+              new MaskFilter.blur(BlurStyle.normal, 3.0, highQuality: true));
         })
         ..addLayerOnTop(
             new DrawLooperLayerInfo()

examples/raw/shadow.dart

@@ -21,7 +21,7 @@ void beginFrame(double timeStamp) {
         (Paint layerPaint) {
       layerPaint.color = const Color.fromARGB(128, 55, 55, 55);
       layerPaint.setMaskFilter(
-          new MaskFilter.Blur(BlurStyle.normal, 5.0, highQuality: true));
+          new MaskFilter.blur(BlurStyle.normal, 5.0, highQuality: true));
     })
     // Main layer.
     ..addLayerOnTop(new DrawLooperLayerInfo(), (Paint) {});