Battery Status API: blink promise implementation and layout tests.

Source/modules/battery/BatteryManager.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/battery/BatteryManager.h"
 
 #include "RuntimeEnabledFeatures.h"
 #include "modules/battery/BatteryDispatcher.h"
 #include "modules/battery/BatteryStatus.h"
 
 namespace WebCore {
 
 PassRefPtrWillBeRawPtr<BatteryManager> BatteryManager::create(ExecutionContext* context)
 {
     RefPtrWillBeRawPtr<BatteryManager> batteryManager(adoptRefWillBeRefCountedGarbageCollected(new BatteryManager(context)));
     batteryManager->suspendIfNeeded();
     return batteryManager.release();
 }
 
 BatteryManager::~BatteryManager()
 {
     stopUpdating();
 }
 
 BatteryManager::BatteryManager(ExecutionContext* context)
     : ActiveDOMObject(context)
     , DeviceEventControllerBase(toDocument(context)->page())
     , m_batteryStatus(BatteryStatus::create())
+    , m_state(NotStarted)
 {
-    m_hasEventListener = true;
-    startUpdating();
+}
+
+ScriptPromise BatteryManager::startRequest(ScriptState* scriptState)
+{
+    if (m_state == Pending)
+        return m_resolver->promise();
+
+    m_resolver = ScriptPromiseResolverWithContext::create(scriptState);
+    ScriptPromise promise = m_resolver->promise();
+
+    if (m_state == Resolved) {
+        // FIXME: Consider returning the same promise in this case. See crbug.com/385025.
+        m_resolver->resolve(this);
+    } else if (m_state == NotStarted) {
+        m_state = Pending;
+        m_hasEventListener = true;
+        startUpdating();
+    }
+
+    return promise;
 }
 
 bool BatteryManager::charging()
 {
     return m_batteryStatus->charging();
 }
 
 double BatteryManager::chargingTime()
 {
     return m_batteryStatus->chargingTime();
 }
 
 double BatteryManager::dischargingTime()
 {
     return m_batteryStatus->dischargingTime();
 }
 
 double BatteryManager::level()
 {
     return m_batteryStatus->level();
 }
 
 void BatteryManager::didUpdateData()
 {
     ASSERT(RuntimeEnabledFeatures::batteryStatusEnabled());
+    ASSERT(m_state != NotStarted);
 
     RefPtr<BatteryStatus> oldStatus = m_batteryStatus;
     m_batteryStatus = BatteryDispatcher::instance().latestData();
 
     // BatteryDispatcher also holds a reference to m_batteryStatus.
     ASSERT(m_batteryStatus->refCount() > 1);
 
+    if (m_state == Pending) {
+        ASSERT(m_resolver);
+        m_state = Resolved;
+        m_resolver->resolve(this);
+        return;
+    }
+
     Document* document = toDocument(executionContext());
     if (document->activeDOMObjectsAreSuspended() || document->activeDOMObjectsAreStopped())
         return;
 
     ASSERT(oldStatus);
 
     if (m_batteryStatus->charging() != oldStatus->charging())
         dispatchEvent(Event::create(EventTypeNames::chargingchange));
     if (m_batteryStatus->chargingTime() != oldStatus->chargingTime())
         dispatchEvent(Event::create(EventTypeNames::chargingtimechange));
@@ skipping 30 matching lines @@
     startUpdating();
 }
 
 void BatteryManager::stop()
 {
     m_hasEventListener = false;
     stopUpdating();
 }
 
 } // namespace WebCore