Schedule a frame from IntersectionObserver::observe.

third_party/WebKit/Source/web/tests/IntersectionObserverTest.cpp

+// Copyright 2016 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 "core/dom/IntersectionObserver.h"
+
+#include "core/dom/IntersectionObserverCallback.h"
+#include "core/dom/IntersectionObserverInit.h"
+#include "platform/testing/UnitTestHelpers.h"
+#include "web/WebViewImpl.h"
+#include "web/tests/sim/SimCompositor.h"
+#include "web/tests/sim/SimDisplayItemList.h"
+#include "web/tests/sim/SimRequest.h"
+#include "web/tests/sim/SimTest.h"
+#include "wtf/CurrentTime.h"
+
+namespace blink {
+
+namespace {
+
+class TestIntersectionObserverCallback : public IntersectionObserverCallback {
+public:
+    TestIntersectionObserverCallback(Document& document) : m_document(document), m_callCount(0) { }
+    void handleEvent(const HeapVector<Member<IntersectionObserverEntry>>&, IntersectionObserver&) override { m_callCount++; }
+    ExecutionContext* getExecutionContext() const override { return m_document; }
+    int callCount() const { return m_callCount; }
+
+    DEFINE_INLINE_TRACE() {
+        IntersectionObserverCallback::trace(visitor);
+        visitor->trace(m_document);
+    }
+
+private:
+    Member<Document> m_document;
+    int m_callCount;
+};
+
+} // namespace
+
+class IntersectionObserverTest : public SimTest { };
+
+TEST_F(IntersectionObserverTest, ObserveSchedulesFrame)
+{
+    SimRequest mainResource("https://example.com/", "text/html");
+    loadURL("https://example.com/");
+    mainResource.complete("<div id='target'></div>");
+
+    IntersectionObserverInit observerInit;
+    TrackExceptionState exceptionState;
+    TestIntersectionObserverCallback* observerCallback = new TestIntersectionObserverCallback(document());
+    IntersectionObserver* observer = IntersectionObserver::create(observerInit, *observerCallback, exceptionState);
+    ASSERT_FALSE(exceptionState.hadException());
+
+    compositor().beginFrame();
+    ASSERT_FALSE(compositor().needsAnimate());
+    EXPECT_TRUE(observer->takeRecords().isEmpty());
+    EXPECT_EQ(observerCallback->callCount(), 0);
+
+    Element* target = document().getElementById("target");
+    ASSERT_TRUE(target);
+    observer->observe(target);
+    EXPECT_TRUE(compositor().needsAnimate());
+}
+
+} // namespace blink