Adds NetInfo v3 Web API to Blink.

Source/modules/netinfo/NetworkInformation.cpp

+// 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 "modules/netinfo/NetworkInformation.h"
+
+#include "core/dom/ExecutionContext.h"
+#include "core/page/NetworkStateNotifier.h"
+#include "modules/EventTargetModules.h"
+
+namespace {
+
+const char kCellular[] = "cellular";
+const char kBluetooth[] = "bluetooth";
+const char kEthernet[] = "ethernet";
+const char kWifi[] = "wifi";
+const char kOther[] = "other";
+const char kNone[] = "none";
+
+String connectionTypeToString(blink::WebConnectionType type)
+{
+    switch (type) {
+    case blink::ConnectionTypeCellular:
+        return kCellular;

[Inactive, 2014/05/28 20:18:20]

So we keep constructing WTF Strings from const char* here? Shouldn't we use
DEFINE_STATIC_LOCAL() macro and define those as static Strings?

[jkarlin, 2014/05/29 11:37:56]

Thanks for the suggestion!  Done.

+    case blink::ConnectionTypeBluetooth:
+        return kBluetooth;
+    case blink::ConnectionTypeEthernet:
+        return kEthernet;
+    case blink::ConnectionTypeWifi:
+        return kWifi;
+    case blink::ConnectionTypeOther:
+        return kOther;
+    case blink::ConnectionTypeNone:
+        return kNone;
+    }
+    ASSERT_NOT_REACHED();
+    return kNone;
+}
+
+} // namespace
+
+namespace WebCore {
+
+PassRefPtrWillBeRawPtr<NetworkInformation> NetworkInformation::create(ExecutionContext* context)
+{
+    RefPtrWillBeRawPtr<NetworkInformation> connection(adoptRefWillBeRefCountedGarbageCollected(new NetworkInformation(context)));
+    connection->suspendIfNeeded();
+    return connection.release();
+}
+
+NetworkInformation::~NetworkInformation()
+{
+    ASSERT(!m_observing);
+}
+
+String NetworkInformation::type() const
+{
+    return connectionTypeToString(m_type);
+}
+
+void NetworkInformation::connectionTypeChange(blink::WebConnectionType type)
+{
+    ASSERT(executionContext()->isContextThread());
+
+    // This can happen if the observer removes and then adds itself again
+    // during notification.
+    if (m_type == type)
+        return;
+
+    m_type = type;
+    dispatchEvent(Event::create(EventTypeNames::typechange));

[Inactive, 2014/05/28 20:18:20]

The spec says to queue the event but it seems we are firing synchronously? I
don't know it if matters here, just pointing this out.

[adamk, 2014/05/28 22:44:08]

I noticed this too, but I think we're effectively doing what the spec says:
since the browser process notifies the renderer via IPC, connectionTypeChange
only ever runs as a consequence of having been queued as a task. And indeed, we
only set m_type immediately before dispatching the event.

[Inactive, 2014/05/28 22:47:28]

It makes sense, thanks for clarifying.

[jkarlin, 2014/05/29 11:37:56]

Done.

[jkarlin, 2014/05/29 11:39:45]

I should clarify that by 'done' I'm just agreeing that we're already queuing the
task, no change was made to the code.

+}
+
+const AtomicString& NetworkInformation::interfaceName() const
+{
+    return EventTargetNames::NetworkInformation;
+}
+
+ExecutionContext* NetworkInformation::executionContext() const
+{
+    return ActiveDOMObject::executionContext();
+}
+
+bool NetworkInformation::addEventListener(const AtomicString& eventType, PassRefPtr<EventListener> listener, bool useCapture)
+{
+    if (!EventTargetWithInlineData::addEventListener(eventType, listener, useCapture))
+        return false;
+    startObserving();
+    return true;
+}
+
+bool NetworkInformation::removeEventListener(const AtomicString& eventType, EventListener* listener, bool useCapture)
+{
+    if (!EventTargetWithInlineData::removeEventListener(eventType, listener, useCapture))
+        return false;
+    if (!hasEventListeners())
+        stopObserving();
+    return true;
+}
+
+void NetworkInformation::removeAllEventListeners()
+{
+    EventTargetWithInlineData::removeAllEventListeners();
+    ASSERT(!hasEventListeners());
+    stopObserving();
+}
+
+bool NetworkInformation::hasPendingActivity() const
+{
+    ASSERT(hasEventListeners() == m_observing);
+
+    // Prevent collection of this object when there are active listeners.
+    return m_observing;
+}
+
+void NetworkInformation::stop()
+{
+    stopObserving();
+}
+
+void NetworkInformation::startObserving()
+{
+    if (!m_observing) {
+        networkStateNotifier().addObserver(this, executionContext());
+        m_observing = true;
+    }
+}
+
+void NetworkInformation::stopObserving()
+{
+    if (m_observing) {
+        networkStateNotifier().removeObserver(this, executionContext());
+        m_observing = false;
+    }
+}
+
+NetworkInformation::NetworkInformation(ExecutionContext* context)
+    : ActiveDOMObject(context)
+    , m_observing(false)
+{
+    ScriptWrappable::init(this);
+    m_type = networkStateNotifier().connectionType();

[Inactive, 2014/05/28 20:18:20]

nit: Could be in the initializer list?

[jkarlin, 2014/05/29 11:37:56]

Done.

+}
+
+} // namespace WebCore