2014-05-05  Ion Rosca  <rosca@adobe.com>

        [CSS Blending] Changing isolation CSS property should not trigger repaint in RenderStyle::changeRequiresLayerRepaint

        https://bugs.webkit.org/show_bug.cgi?id=131436

        The isolation:isolate property will create a stacking context. This is done in

        StyleResolver::adjustRenderStyle when z-index is forced to 0 if it was auto before.

        If the element is already a stacking context for any other reason, isolation flag

        will not have any effect.

        Reviewed by NOBODY (OOPS!).

        Tests: fast/repaint/blend-mode-turn-off-isolation-no-effect.html

               fast/repaint/blend-mode-turn-off-isolation.html

        * rendering/style/RenderStyle.cpp:

        (WebCore::RenderStyle::changeRequiresLayerRepaint):

        do not return true if isolation has changed.

2014-05-05  Ion Rosca  <rosca@adobe.com>

        [CSS Blending] Changing isolation CSS property should not trigger repaint in RenderStyle::changeRequiresLayerRepaint

        https://bugs.webkit.org/show_bug.cgi?id=131436

        Reviewed by NOBODY (OOPS!).

        * fast/repaint/blend-mode-turn-off-isolation-expected.txt: Added.

        * fast/repaint/blend-mode-turn-off-isolation-no-effect-expected.txt: Added.

        * fast/repaint/blend-mode-turn-off-isolation-no-effect.html: Added.

        * fast/repaint/blend-mode-turn-off-isolation.html: Added.

This test checks that removing isolation from an element not being stacking context for other reasons will repaint the blending div.

(repaint rects

  (rect 58 68 100 100)

)

This test checks that removing isolation from an element being stacking context for other reasons will not trigger any repaint.

<!DOCTYPE HTML>

<html>

    <head>

        <style>

            div {

                width: 100px;

                height: 100px;

            }

            .stacking-context {

                position: relative;

                z-index: 1;

            }

            .isolating {

                -webkit-isolation: isolate;

                isolation: isolate;

            }

            .blending {

                -webkit-mix-blend-mode: difference;

                mix-blend-mode: difference;

            }

        </style>

        <script src="resources/text-based-repaint.js" type="text/javascript"></script>

    </head>

    <body>

        <p>This test checks that removing isolation from an element being stacking context for other reasons will not trigger any repaint.</p>

        <div id="target" class="stacking-context isolating" style="background-color: #00ff00;">

            <div class="blending" style="background-color: #ff00ff; margin-left: 50px;"></div>

        </div>

        <script type="text/javascript">

        function repaintTest() {

            var target = document.getElementById("target");

            target.className = "stacking-context";

        }

        window.onload = function() {

            if (window.testRunner)

                window.testRunner.dumpAsText(true);

            runRepaintTest();

        }

        </script>

    </body>

</html>

<!DOCTYPE HTML>

<html>

    <head>

        <style>

            div {

                width: 100px;

                height: 100px;

            }

            .isolating {

                -webkit-isolation: isolate;

                isolation: isolate;

            }

            .blending {

                -webkit-mix-blend-mode: difference;

                mix-blend-mode: difference;

            }

        </style>

        <script src="resources/text-based-repaint.js" type="text/javascript"></script>

    </head>

    <body>

        <p>This test checks that removing isolation from an element not being stacking context for other reasons will repaint the blending div.</p>

        <div id="target" class="isolating" style="background-color: #00ff00;">

            <div class="blending" style="background-color: #ff00ff; margin-left: 50px;"></div>

        </div>

        <script type="text/javascript">

        function repaintTest() {

            var target = document.getElementById("target");

            target.className = "";

        }

        window.onload = function() {

            if (window.testRunner)

                window.testRunner.dumpAsText(true);

            runRepaintTest();

        }

        </script>

    </body>

</html>