Adding the 'filter' context attribute to 2D canvas

LayoutTests/fast/canvas/canvas-filter-svg-bbox.html

Index: LayoutTests/fast/canvas/canvas-filter-svg-bbox.html
diff --git a/LayoutTests/fast/canvas/canvas-filter-svg-bbox.html b/LayoutTests/fast/canvas/canvas-filter-svg-bbox.html
new file mode 100644
index 0000000000000000000000000000000000000000..a2b032201b888753919329c226cb7d8811c17700
--- /dev/null
+++ b/LayoutTests/fast/canvas/canvas-filter-svg-bbox.html
@@ -0,0 +1,18 @@
+<svg style="display: block; width: 0; height: 0">
+  <defs>
+    <filter id="color-matrix">
+      <fecolormatrix type="matrix" in="SourceGraphic" values="0 0 0 0 0 
+                0 0 0 0 1 
+                0 0 0 0 0 
+                0 0 0 0 1"></fecolormatrix>
+    </filter>
+  </defs>
+</svg>
+<canvas id="canvas" width="100" height="100"></canvas>
+<script>
+var canvas = document.getElementById('canvas');
+var ctx = canvas.getContext('2d');
+ctx.filter = 'url(#color-matrix)';
+ctx.fillStyle = '#fff';
+ctx.fillRect(25, 25, 50, 50);
+</script>