Don't anti-alias backgrounds of images.

LayoutTests/paint/images/image-backgrounds-not-antialiased.html

Index: LayoutTests/paint/images/image-backgrounds-not-antialiased.html
diff --git a/LayoutTests/paint/images/image-backgrounds-not-antialiased.html b/LayoutTests/paint/images/image-backgrounds-not-antialiased.html
new file mode 100644
index 0000000000000000000000000000000000000000..736e561d2a43d51c9718166a5bd17c38be883db0
--- /dev/null
+++ b/LayoutTests/paint/images/image-backgrounds-not-antialiased.html
@@ -0,0 +1,25 @@
+<style type="text/css">

[leviw_travelin_and_unemployed, 2014/11/11 00:19:50]

Nit: doctype.

Why not a ref test with the image sans background color?

+.mi {
+background-color: #f00; /* Just makes the bug visible. */
+margin-top: 1px; /* Precondition for bug. */
+width: 395px; /* Not important. */
+height: 296px; /* Not important. */
+}
+</style>
+
+<!-- With an anti-aliased background, this image will show a row of red pixels at the top at
+device pixel ration 3.5. To fix this, we turn off anti-aliasing for image backgrounds.
+ -->
+ <img class="mi" id="target" src="../../http/tests/resources/square20.jpg"> -->
+
+<script>
+window.onload = function () {
+    if (window.internals && window.testRunner)
+        testRunner.setBackingScaleFactor(3.7, finishTest);
+}
+
+function finishTest() {
+    if (window.testRunner)
+        window.testRunner.notifyDone();
+}
+</script>