Use C++11 range-based loop for core/clipboard, core/dom and core/testing

Source/core/dom/IdTargetObserverRegistry.cpp

Index: Source/core/dom/IdTargetObserverRegistry.cpp
diff --git a/Source/core/dom/IdTargetObserverRegistry.cpp b/Source/core/dom/IdTargetObserverRegistry.cpp
index 978c1d387ac8bc0931f8dfaf8bf807639df07a0e..63b2002a77aeb0f95349526d4a3a7f662673d6d1 100644
--- a/Source/core/dom/IdTargetObserverRegistry.cpp
+++ b/Source/core/dom/IdTargetObserverRegistry.cpp
@@ -79,9 +79,9 @@ void IdTargetObserverRegistry::notifyObserversInternal(const AtomicString& id)
 
     WillBeHeapVector<RawPtrWillBeMember<IdTargetObserver> > copy;
     copyToVector(*m_notifyingObserversInSet, copy);
-    for (WillBeHeapVector<RawPtrWillBeMember<IdTargetObserver> >::const_iterator it = copy.begin(); it != copy.end(); ++it) {
-        if (m_notifyingObserversInSet->contains(*it))
-            (*it)->idTargetChanged();
+    for (const auto& observer : copy) {
+        if (m_notifyingObserversInSet->contains(observer))
+            observer->idTargetChanged();
     }
 
     if (m_notifyingObserversInSet->isEmpty())