Replacing non-portable CanvasRenderingContext.setFillColor with more portable variants.

tests/html/canvas_test.dart

 #library('CanvasTest');
 #import('../../pkg/unittest/unittest.dart');
 #import('../../pkg/unittest/html_config.dart');
 #import('dart:html');
 
 main() {
   CanvasElement canvas;
   CanvasRenderingContext2D context;
   int width = 100;
   int height = 100;
@@ skipping 18 matching lines @@
     checkPixel(data, 30 + width * 10, [0, 0, 0, 0]);
   });
   test('FillStyleGradient', () {
     var gradient = context.createLinearGradient(0,0,20,20);
     gradient.addColorStop(0,'red');
     gradient.addColorStop(1,'blue');
     context.fillStyle = gradient;
     context.fillRect(0, 0, 20, 20);
     expect(context.fillStyle is CanvasGradient, isTrue);
   });
-  test('SetFillColor', () {
-    // With floats.
-    context.setFillColor(10, 10, 10, 10);
-    context.fillRect(10, 10, 20, 20);
-
-    // With rationals.
-    context.setFillColor(10.0, 10.0, 10.0, 10.0);
-    context.fillRect(20, 20, 30, 30);
-
-    // With ints.
-    context.setFillColor(10, 10, 10, 10);
-    context.fillRect(30, 30, 40, 40);
-
-    // TODO(vsm): Verify the result once we have the ability to read pixels.
-  });
   test('StrokeStyle', () {
     context.strokeStyle = "blue";
     context.strokeRect(30, 30, 10, 20);
 
     // TODO(vsm): Verify the result once we have the ability to read pixels.
   });
   test('CreateImageData', () {
     ImageData image = context.createImageData(canvas.width,
                                               canvas.height);
     Uint8ClampedArray data = image.data;
@@ skipping 17 matching lines @@
   });
 }
 
 void checkPixel(Uint8ClampedArray data, int offset, List<int> rgba)
 {
   offset *= 4;
   for (var i = 0; i < 4; ++i) {
     expect(data[offset + i], equals(rgba[i]));
   }
 }