Composited Animations: Introduce pixel-ref layout tests.

LayoutTests/animations/resources/composited-animations-data/rotate-scale.js

+
+var animateRotate = {
+  keyframes: [
+    {rotate: '-10deg'},
+    {rotate: '470deg'}
+  ],
+  color: 'maroon',
+  margin: 5,
+  stamps: [

[dstockwell, 2015/08/06 00:23:19]

Why isn't this just an array of numbers?

`stamps` doesn't seem like the best name, perhaps `times` or `samples`?

[loyso (OOO), 2015/09/14 06:19:07]

I want to keep it extensible so we can add extra properties to individual
samples.
`samples` is great, thanks!

+    {at: 0},
+    {at: 0.05},
+    {at: 0.15},
+    {at: 0.25},
+    {at: 0.35},
+    {at: 0.45},
+    {at: 0.5},
+    {at: 0.55},
+    {at: 0.65},
+    {at: 0.75},
+    {at: 0.85},
+    {at: 0.95},
+    {at: 1.05},
+    {at: 1.15},
+  ]
+};
+
+var animateScale = {
+  keyframes: [
+    {scale: '0.1'},
+    {scale: '1'}
+  ],
+  color: 'peru',
+  margin: 5,
+  marker: false, // TODO(loyso): This mustn't affect cc/blink consistency.

[Ian Vollick, 2015/08/05 13:58:46]

What do you mean by this TODO?

[loyso (OOO), 2015/09/14 06:19:07]

Done.

+  stamps: [

[Ian Vollick, 2015/08/05 13:58:46]

Just to make sure I'm understanding how your test works, in order to test a
number of time fractions with a single pixel result, you're creating a new
element for each stamp so you can check them simultaneously?

[loyso (OOO), 2015/08/06 06:44:18]

Yes, that's correct. See the comments in composited-animation-test.js

+    {at: 0},
+    {at: 0.05},
+    {at: 0.15},
+    {at: 0.25},
+    {at: 0.35},
+    {at: 0.45},
+    {at: 0.5},
+    {at: 0.55},
+    {at: 0.65},
+    {at: 0.75},
+    {at: 0.85},
+    {at: 0.95},
+    {at: 1.05},
+    {at: 1.15},
+  ]
+};
+
+var rotateScaleTests = [animateRotate, animateScale];
+