Mark the AtomicString(const String&) constructor as explicit

Source/core/svg/SVGAElement.cpp

Index: Source/core/svg/SVGAElement.cpp
diff --git a/Source/core/svg/SVGAElement.cpp b/Source/core/svg/SVGAElement.cpp
index 4f3536c6e349c6326780fdf4f39491df831ddb18..2f51ae789f0aba22abb4861c6bbe9fc88472ed33 100644
--- a/Source/core/svg/SVGAElement.cpp
+++ b/Source/core/svg/SVGAElement.cpp
@@ -172,9 +172,9 @@ void SVGAElement::defaultEventHandler(Event* event)
                     return;
             }
 
-            String target = this->target();
+            AtomicString target = this->target();
             if (target.isEmpty() && fastGetAttribute(XLinkNames::showAttr) == "new")
-                target = "_blank";
+                target = AtomicString("_blank", AtomicString::ConstructFromLiteral);
             event->setDefaultHandled();
 
             Frame* frame = document().frame();