Use C++11 range-based loop in core/frame

Source/core/frame/Frame.cpp

Index: Source/core/frame/Frame.cpp
diff --git a/Source/core/frame/Frame.cpp b/Source/core/frame/Frame.cpp
index 302a3e1e1328c2dd483c8800fa04416b5323c0b4..61e819ca91f8bd280ebe688b54a1c817c9d19760 100644
--- a/Source/core/frame/Frame.cpp
+++ b/Source/core/frame/Frame.cpp
@@ -109,9 +109,8 @@ void Frame::detachChildren()
     childrenToDetach.reserveCapacity(tree().childCount());
     for (Frame* child = tree().firstChild(); child; child = child->tree().nextSibling())
         childrenToDetach.append(child);
-    FrameVector::iterator end = childrenToDetach.end();
-    for (FrameVector::iterator it = childrenToDetach.begin(); it != end; ++it)
-        (*it)->detach();
+    for (const auto& child : childrenToDetach)
+        child->detach();
 }
 
 FrameHost* Frame::host() const