Test framework and tests for CSSOM View smooth scroll

LayoutTests/fast/scroll-behavior/resources/scroll-behavior-test.js

Index: LayoutTests/fast/scroll-behavior/resources/scroll-behavior-test.js
diff --git a/LayoutTests/fast/scroll-behavior/resources/scroll-behavior-test.js b/LayoutTests/fast/scroll-behavior/resources/scroll-behavior-test.js
new file mode 100644
index 0000000000000000000000000000000000000000..39573fc06bd92e1304b0e3b3c35381f8af386d06
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+++ b/LayoutTests/fast/scroll-behavior/resources/scroll-behavior-test.js
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+// A ScrollBehaviorTest runs a set of ScrollBehaviorTestCases. The only
+// ScrollBehaviorTest method that should be called by external code is run().
+
+// Creates a ScrollBehaviorTest where |scrollElement| is the element being
+// scrolled, |scrollEventTarget| is the target for scroll events for |scrollElement|,
+// and |testsCases| is an array of ScrollBehaviorTestCases.
+function ScrollBehaviorTest(scrollElement, scrollEventTarget, testCases) {
+    this.scrollElement = scrollElement;
+    this.scrollEventTarget = scrollEventTarget;
+    this.testCases = testCases;
+    this.currentTestCase = 0;
+}
+
+ScrollBehaviorTest.prototype.scrollListener = function(testCase) {
+    if (testCase.waitForEnd) {
+        if (this.scrollElement.scrollLeft == testCase.endX && this.scrollElement.scrollTop == testCase.endY)
+            this.testCaseComplete();
+        return;
+    }
+
+    // Wait for an intermediate frame, then instant-scroll to the end state.
+    if ((this.scrollElement.scrollLeft != testCase.startX || this.scrollElement.scrollTop != this.scrollElement.startY) &&
+        (this.scrollElement.scrollLeft != testCase.endX || this.scrollElement.scrollTop != this.scrollElement.endY)) {
+        this.scrollElement.scrollLeft = {x: testCase.endX, behavior: "instant"};
+        this.scrollElement.scrollTop = {y: testCase.endY, behavior: "instant"};
+        this.testCaseComplete();
+    }
+};
+
+ScrollBehaviorTest.prototype.startNextTestCase = function() {
+    if (this.currentTestCase >= this.testCases.length) {
+        this.allTestCasesComplete();
+        return;
+    }
+
+    var testCase = this.testCases[this.currentTestCase];
+    var isSmoothTest = (testCase.js == "smooth" || (testCase.css == "smooth" && testCase.js != "instant"));
+
+    this.asyncTest = async_test("Scroll to x:" + testCase.x + ", y:" + testCase.y + ", smooth:" + isSmoothTest);
+
+    testCase.setStartPosition(this.scrollElement.scrollLeft, this.scrollElement.scrollTop);
+    testCase.run();
+
+    var scrollElement = this.scrollElement;
+    if (isSmoothTest) {
+        this.asyncTest.step(function() {
+            assert_equals(scrollElement.scrollLeft + ", " + scrollElement.scrollTop, testCase.startX + ", " + testCase.startY);
+        });
+        testCase.scrollListener = this.scrollListener.bind(this, testCase);
+        this.scrollEventTarget.addEventListener("scroll", testCase.scrollListener);
+    } else {
+        this.asyncTest.step(function() {
+            assert_equals(scrollElement.scrollLeft + ", " + scrollElement.scrollTop, testCase.endX + ", " + testCase.endY);
+        });
+        this.testCaseComplete();
+    }
+}
+
+ScrollBehaviorTest.prototype.testCaseComplete = function() {
+    var currentScrollListener = this.testCases[this.currentTestCase].scrollListener;
+    if (currentScrollListener) {
+        this.scrollEventTarget.removeEventListener("scroll", currentScrollListener);
+    }
+    this.asyncTest.done();
+
+    this.currentTestCase++;
+    this.startNextTestCase();
+}
+
+ScrollBehaviorTest.prototype.run = function() {
+    setup({explicit_done: true});
+    this.startNextTestCase();
+}
+
+ScrollBehaviorTest.prototype.allTestCasesComplete = function() {
+    done();
+}
+
+
+// A ScrollBehaviorTestCase represents a single scroll. Subclasses should provide
+// a run() method that carries out the scroll (e.g., by calling scrollTo, scroll,
+// or scrollBy, or setting scrollLeft or scrollTop).
+
+// Creates a ScrollBehaviorTestCase. |testData| is a dictionary with fields:
+// css - Value of scroll-behavior CSS property.
+// js - (optional) Value of scroll behavior used in javascript.
+// x, y - Coordinates to be used when carrying out the scroll.
+// waitForEnd - (must be provided for smooth scrolls) Whether the test runner should
+//              wait until the scroll is complete, rather than only waiting until
+//              the scroll is underway.
+function ScrollBehaviorTestCase(testData) {
+    this.js = testData.js;
+    this.css = testData.css;
+    this.waitForEnd = testData.waitForEnd;
+    this.x = testData.x;
+    this.y = testData.y;
+}
+
+// Sets the starting scroll position for this test case. Subclasses should override
+// this if the expected end position depends on the start position rather than
+// only on this.x and this.y.
+ScrollBehaviorTestCase.prototype.setStartPosition = function(currentX, currentY) {
+    this.startX = currentX;
+    this.startY = currentY;
+    this.endX = this.x;
+    this.endY = this.y;
+}