Implement left property animation on InvalidatableStyleInterpolation

Source/core/animation/LengthPropertyFunctions.cpp

Index: Source/core/animation/LengthPropertyFunctions.cpp
diff --git a/Source/core/animation/LengthPropertyFunctions.cpp b/Source/core/animation/LengthPropertyFunctions.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..64d133fc49981883a37d3538c6b4642ae0973772
--- /dev/null
+++ b/Source/core/animation/LengthPropertyFunctions.cpp
@@ -0,0 +1,38 @@
+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "config.h"
+#include "core/animation/LengthPropertyFunctions.h"
+
+#include "core/style/ComputedStyle.h"
+
+namespace blink {
+
+// TODO(alancutter): Generate these functions.
+
+ValueRange LengthPropertyFunctions::valueRange(CSSPropertyID property)
+{
+    ASSERT(property == CSSPropertyLeft);
+    return ValueRangeAll;
+}
+
+bool LengthPropertyFunctions::getPixelsForKeyword(CSSPropertyID property, CSSValueID valueID, double& result)
+{
+    ASSERT(property == CSSPropertyLeft);
+    return false;
+}
+
+bool LengthPropertyFunctions::getLength(CSSPropertyID property, const ComputedStyle& style, Length& result)
+{
+    ASSERT(property == CSSPropertyLeft);
+    result = style.left();
+    return true;
+}
+
+bool LengthPropertyFunctions::getInitialLength(CSSPropertyID property, Length& result)
+{
+    return getLength(property, *ComputedStyle::initialStyle(), result);
+}
+
+} // namespace blink