CssStyleDeclaration setProperty doesn't work with -webkit-* properties

[DartBot]

This issue was originally filed by djean...@google.com

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What steps will reproduce the problem?

      DivElement e = querySelector("#a-div");
      e.style.setProperty("-webkit-mask-image", "-webkit-gradient(linear, "
          "left top, right top, "
          "from(rgba(0,0,0,0)), "
          "color-stop(0.7, rgba(0,0,0,0)), "
          "to(rgba(0,0,0,1)));");
      print("with setProperty: ${e.style.getPropertyValue("-webkit-mask-image")}");
      e.style.cssText = "-webkit-mask-image: -webkit-gradient(linear, "
          "left top, right top, "
          "from(rgba(0,0,0,0)), "
          "color-stop(0.7, rgba(0,0,0,0)), "
          "to(rgba(0,0,0,1)));";
      print("with cssText: ${e.style.getPropertyValue("-webkit-mask-image")}");

      e.style.setProperty("opacity", "0.7");
      print("with setProperty: ${e.style.getPropertyValue("opacity")}");
      e.style.cssText = "opacity: 0.7;";
      print("with cssText: ${e.style.getPropertyValue("opacity")}");

What is the expected output? What do you see instead?

Result:
with setProperty:
with cssText: -webkit-gradient(linear, 0% 0%, 100% 0%, from(rgba(0, 0, 0, 0)), color-stop(0.7, rgba(0, 0, 0, 0)), to(rgb(0, 0, 0)))
with setProperty: 0.7
with cssText: 0.7

Expected:
with setProperty: -webkit-gradient(linear, 0% 0%, 100% 0%, from(rgba(0, 0, 0, 0)), color-stop(0.7, rgba(0, 0, 0, 0)), to(rgb(0, 0, 0)))
with cssText: -webkit-gradient(linear, 0% 0%, 100% 0%, from(rgba(0, 0, 0, 0)), color-stop(0.7, rgba(0, 0, 0, 0)), to(rgb(0, 0, 0)))
with setProperty: 0.7
with cssText: 0.7

What version of the product are you using? On what operating system?
Linux, 1.4.0-dev.2.0

Please provide any additional information below.

[sethladd]

Added Library-Html, Area-Library, Triaged labels.

[efortuna]

Setting status to "Waiting". I filed a bug on Chrome, but basically this seems to be a Chrome issue rather than a Dart one.

Blocked on the surrounding Chrome bug: https://code.google.com/p/chromium/issues/detail?id=406109

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Added Waiting label.

[alan-knight]

Still waiting...