Convert some pixel tests in fast/canvas into ref tests.

LayoutTests/fast/canvas/canvas-transform-skewed.html

Index: LayoutTests/fast/canvas/canvas-transform-skewed.html
diff --git a/LayoutTests/fast/canvas/canvas-transform-skewed.html b/LayoutTests/fast/canvas/canvas-transform-skewed.html
index f3ff910e17bb88c9681c4faea0e68c5d9ee7afe0..4618604b0ccfb67a193e7a01a464deccc6a05317 100644
--- a/LayoutTests/fast/canvas/canvas-transform-skewed.html
+++ b/LayoutTests/fast/canvas/canvas-transform-skewed.html
@@ -5,17 +5,16 @@
 <title>Canvas test: 2d.transformation.transform.skewed</title>
 <canvas id="canvas" class="output" width="100" height="100"><p class="fallback">FAIL (fallback content)</p></canvas>
 <script>
-if (window.testRunner)
-  testRunner.dumpAsTextWithPixelResults();
-
 var ctx = document.getElementById("canvas").getContext("2d");
 // Create green with a red square ring inside it
 ctx.fillStyle = '#0f0';
 ctx.fillRect(0, 0, 100, 100);
 ctx.fillStyle = '#f00';
-ctx.fillRect(20, 10, 60, 30);
+// ctx.fillRect(20, 10, 60, 30); Inset by 1 pixel to allow margin for numerical error.

[Stephen White, 2014/03/05 21:29:33]

Nit: please remove commented-out code.

+ctx.fillRect(21, 11, 58, 28);
 ctx.fillStyle = '#0f0';
-ctx.fillRect(40, 20, 20, 10);
+// ctx.fillRect(40, 20, 20, 10); Outset by one pixel to allow margin for numerical error.

[Stephen White, 2014/03/05 21:29:33]

Same here.

+ctx.fillRect(39, 19, 22, 12);
 
 // Draw a skewed shape to fill that gap, to make sure it is aligned correctly
 ctx.transform(1,4, 2,3, 5,6);