Bug 817700 - Fix test_mozGetAsFile canvas test. r=roc

content/canvas/test/test_mozGetAsFile.html

@@ -7,42 +7,43 @@
 <canvas id="c" width="100" height="50"><p class="fallback">FAIL (fallback content)</p></canvas>
 <script>
 
-var gCompares = 0;
-
-function compareAsync(file, canvas, type)
+function compareAsync(file, canvas, type, callback)
 {
-  ++gCompares;
-
   var reader = new FileReader();
   reader.onload = 
     function(e) {
       is(e.target.result, canvas.toDataURL(type),
  "<canvas>.mozGetAsFile().getAsDataURL() should equal <canvas>.toDataURL()");
-      if (--gCompares == 0) {
-        SimpleTest.finish();
-      }
+      callback(canvas);
     };
   reader.readAsDataURL(file);
 }
 
+function test1(canvas)
+{
+  var pngfile = canvas.mozGetAsFile("foo.png");
+  is(pngfile.type, "image/png", "Default type for mozGetAsFile should be PNG");
+  compareAsync(pngfile, canvas, "image/png", test2);
+  is(pngfile.name, "foo.png", "File name should be what we passed in");
+}
+
+function test2(canvas)
+{
+  var jpegfile = canvas.mozGetAsFile("bar.jpg", "image/jpeg");
+  is(jpegfile.type, "image/jpeg",
+     "When a valid type is specified that should be returned");
+  compareAsync(jpegfile, canvas, "image/jpeg", SimpleTest.finish);
+  is(jpegfile.name, "bar.jpg", "File name should be what we passed in");
+}
+
 SimpleTest.waitForExplicitFinish();
 addLoadEvent(function () {
 
 var canvas = document.getElementById('c');
 var ctx = canvas.getContext('2d');
-
 ctx.drawImage(document.getElementById('yellow75.png'), 0, 0);
 
-var pngfile = canvas.mozGetAsFile("foo.png");
-is(pngfile.type, "image/png", "Default type for mozGetAsFile should be PNG");
-compareAsync(pngfile, canvas, "image/png");
-is(pngfile.name, "foo.png", "File name should be what we passed in");
-
-var jpegfile = canvas.mozGetAsFile("bar.jpg", "image/jpeg");
-is(jpegfile.type, "image/jpeg",
-   "When a valid type is specified that should be returned");
-compareAsync(jpegfile, canvas, "image/jpeg");
-is(jpegfile.name, "bar.jpg", "File name should be what we passed in");
+test1(canvas);
 
 });
 </script>