Let repaint tests test pixels by default

third_party/WebKit/LayoutTests/fast/repaint/resources/text-based-repaint.js

-// Asynchronous tests should manually call finishRepaintTest at the appropriate
-// time.
-window.testIsAsync = false;
-window.outputRepaintRects = true;
-window.generateMinimumRepaint = false; // See comments about 'Minimum repaint' below.
-
-// All repaint tests are asynchronous.
-if (window.testRunner)
-    testRunner.waitUntilDone();
-
-function runRepaintTest()
-{
-    if (!window.testRunner || !window.internals) {
-        setTimeout(repaintTest, 500);
-        return;
-    }
-
-    // TODO(enne): this is a workaround for multiple svg onload events.
-    // See: http://crbug.com/372946
-    if (window.hasRunRepaintTest)
-        return;
-    window.hasRunRepaintTest = true;
-
-    if (window.enablePixelTesting)
-        testRunner.dumpAsTextWithPixelResults();
-    else
-        testRunner.dumpAsText();
-
-    function continueRepaintTest()
-    {
-        window.internals.startTrackingRepaints(document);
-        repaintTest();
-        if (!window.testIsAsync)
-            finishRepaintTest();
-    }
-
-    if (window.generateMinimumRepaint) {
-        testRunner.capturePixelsAsyncThen(function(width, height, snapshot) {
-            window.widthBeforeRepaint = width;
-            window.heightBeforeRepaint = height;
-            window.snapshotBeforeRepaint = snapshot;
-            continueRepaintTest();
-        });
-    } else {
-        testRunner.layoutAndPaintAsyncThen(continueRepaintTest);
-    };
-}
-
-function runRepaintAndPixelTest()
-{
-    window.enablePixelTesting = true;
-    runRepaintTest();
-}
-
-function forceStyleRecalc()
-{
-    if (document.body)
-        document.body.clientTop;
-    else if (document.documentElement)
-        document.documentElement.clientTop;
-}
-
-function finishRepaintTest()
-{
-    if (!window.testRunner || !window.internals)
-        return;
-
-    // Force a style recalc.
-    forceStyleRecalc();
-
-    var flags = window.internals.LAYER_TREE_INCLUDES_PAINT_INVALIDATIONS;
-
-    if (window.layerTreeAsTextAdditionalFlags)
-        flags |= window.layerTreeAsTextAdditionalFlags;
-
-    var repaintRects = window.internals.layerTreeAsText(document, flags);
-
-    internals.stopTrackingRepaints(document);
-
-    function repaintTestDone()
-    {
-        // Play nice with JS tests which may want to print out assert results.
-        if (window.isJsTest)
-            window.outputRepaintRects = false;
-
-        if (window.outputRepaintRects)
-            testRunner.setCustomTextOutput(repaintRects);
-
-        if (window.afterTest)
-            window.afterTest();
-
-        // Play nice with async JS tests which want to notifyDone themselves.
-        if (!window.jsTestIsAsync)
-            testRunner.notifyDone();
-    }
-
-    if (window.generateMinimumRepaint) {
-        internals.forceFullRepaint(document);
-        testRunner.capturePixelsAsyncThen(function(width, height, snapshot) {
-            if (window.outputRepaintRects) {
-                var minimumRepaint = computeMinimumRepaint(width, height, snapshot);
-                if (minimumRepaint.length)
-                    repaintRects += '\nMinimum repaint:\n' + JSON.stringify(minimumRepaint, null, 2);
-            }
-            repaintTestDone();
-        });
-    } else {
-        repaintTestDone();
-    }
-}
-
-// Minimum repaint
-//
-// Definitions
-// - minimum-repaint = region(diff(snapshot-before-repaintTest,
-//                                 snapshot-after-repaintTest-and-full-repaint))
-//   It includes all pixels that should be changed after repaintTest.
-// - actual-repaint = repaint rects recorded during repaintTest() and
-//   forceStyleRecalc().
-// - potential-under-repaint = subtract(minimum-repaint, actual-repaint)
-//   Potential-under-repaint will be shown in layout test overlay in black if
-//   any minimum-repaint region is not covered by actual-repaint.
-//
-// Potential-under-repaints don't always mean bug:
-// - Some know visualization issues (crbug.com/381221) may cause false
-//   under-repaint;
-// - Screen updates caused by composited layer re-compositing may not need
-//   repaint.
-//
-// How to use
-// 1. Set window.generateMinimumRepaint to true in some repaint test or change
-//    this script to force window.generateMinimumRepaint to true.
-// 2. Run layout tests. Repaint tests will result text diffs, which is because
-//    of the minimum repaint output in the actual results and doesn't mean the
-//    tests failed.
-// 3. In layout test result page, click 'overlay' link or expand the test to
-//    see the 'overlay' pane.
-// 4. Click 'Highlight under-repaint' button. You'll see black region if there
-//    is any under-repaint.
-//
-// Known issues
-//    crbug.com/381221
-
-function computeMinimumRepaint(width, height, snapshot)
-{
-    var result = [];
-    if (width > widthBeforeRepaint) {
-        result.push([widthBeforeRepaint, 0, width - widthBeforeRepaint, Math.max(height, heightBeforeRepaint)]);
-        width = widthBeforeRepaint;
-    }
-    if (height > heightBeforeRepaint) {
-        result.push([0, heightBeforeRepaint, width, height - heightBeforeRepaint]);
-        height = heightBeforeRepaint;
-    }
-
-    var dataBefore = new Uint32Array(snapshotBeforeRepaint);
-    var dataAfter = new Uint32Array(snapshot);
-    var rectsMayContinue = [];
-    var index = 0;
-    for (var y = 0; y < height; ++y) {
-        var x = 0;
-        var rectsMayContinueIndex = 0;
-        var nextRectsMayContinue = [];
-        while (true) {
-            while (x < width && dataBefore[index] == dataAfter[index]) {
-                ++x;
-                ++index;
-            }
-            xBegin = x;
-            while (x < width && dataBefore[index] != dataAfter[index]) {
-                ++x;
-                ++index;
-            }
-            xEnd = x;
-
-            var xWidth = xEnd - xBegin;
-            if (!xWidth)
-                break;
-
-            var rectMayContinue = rectsMayContinue[rectsMayContinueIndex];
-            while (rectMayContinue && rectMayContinue[0] < xBegin)
-                rectMayContinue = rectsMayContinue[++rectsMayContinueIndex];
-
-            if (rectMayContinue && rectMayContinue[0] == xBegin && rectMayContinue[2] == xWidth) {
-                ++rectMayContinue[3];
-                nextRectsMayContinue.push(rectMayContinue);
-            } else {
-                var newRect = [xBegin, y, xWidth, 1];
-                nextRectsMayContinue.push(newRect);
-                result.push(newRect);
-            }
-        }
-        rectsMayContinue = nextRectsMayContinue;
-    }
-    return result;
-}