Have srcset respond to viewport changes

Source/core/frame/ViewportChangeNotifierTest.cpp

Index: Source/core/frame/ViewportChangeNotifierTest.cpp
diff --git a/Source/core/frame/ViewportChangeNotifierTest.cpp b/Source/core/frame/ViewportChangeNotifierTest.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..1ea62fddeb98f7a842853570e541a1f5f56fb435
--- /dev/null
+++ b/Source/core/frame/ViewportChangeNotifierTest.cpp
@@ -0,0 +1,50 @@
+// Copyright 2014 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 "config.h"
+#include "core/frame/ViewportChangeNotifier.h"
+
+#include <gtest/gtest.h>
+
+namespace WebCore {
+
+class TestListener: public ViewportChangeListener {
+public:
+    static PassRefPtrWillBeRawPtr<TestListener> create() { return adoptRefWillBeNoop(new TestListener()); }
+
+    void viewportChanged()
+    {
+        m_listenerCalled = true;
+    }
+
+    TestListener()
+        : m_listenerCalled(false)
+    {
+    }
+
+    bool called() const { return m_listenerCalled; }
+
+private:
+    bool m_listenerCalled;
+};
+
+TEST(ViewportChangeNotifierTest, Basic)
+{
+    OwnPtrWillBeRawPtr<ViewportChangeNotifier> notifier = ViewportChangeNotifier::create();
+    RefPtrWillBeRawPtr<TestListener> listener = TestListener::create();
+    notifier->addListener(listener.get());
+    ASSERT_FALSE(listener->called());
+    notifier->viewportChanged();
+    ASSERT_TRUE(listener->called());
+
+    RefPtrWillBeRawPtr<TestListener> listener2 = TestListener::create();
+    notifier->addListener(listener2.get());
+    ASSERT_FALSE(listener2->called());
+    notifier->removeListener(listener2.get());
+    notifier->viewportChanged();
+    ASSERT_FALSE(listener2->called());
+}
+
+} // namespace
+