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"
+
+using testing::_;

[esprehn, 2016/05/19 22:55:59]

I don't think you use this?

[szager1, 2016/05/19 23:58:40]

Removed.

+
+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;
+    TestIntersectionObserverCallback observerCallback(document());
+    TrackExceptionState exceptionState;
+    IntersectionObserver* observer(IntersectionObserver::create(observerInit, observerCallback, exceptionState));
+    ASSERT_FALSE(exceptionState.hadException());
+
+    compositor().beginFrame();
+    webView().updateAllLifecyclePhases();

[esprehn, 2016/05/19 22:55:59]

remove this, beginFrame does it

[szager1, 2016/05/19 23:58:40]

Done.

+    testing::runPendingTasks();

[esprehn, 2016/05/19 22:55:59]

Why do you need to run tasks?

[szager1, 2016/05/19 23:58:40]

beginFrame() will schedule a task to generate a frame, but the test needs to
make sure a frame was generated and the document is compositing-clean at this
point.  I cargo-culted this from FrameThrottlingTest::compositeFrame(), and it
works as expected.

[esprehn, 2016/05/20 00:38:34]

beginFrame() doesn't schedule a task to generate a frame, it does it right then.
The FrameThrottlingTest is a special case where they want to pump tasks since
one of those tasks will toggle the throttling behavior async. Most tests don't
need to do that, you shouldn't need to either.

[szager1, 2016/05/20 17:22:39]

Indeed, I see you're right; I removed the call to runPendingTasks.

+    EXPECT_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