Make calls to AtomicString(const String&) explicit in web/

Source/core/loader/FormSubmission.cpp

Index: Source/core/loader/FormSubmission.cpp
diff --git a/Source/core/loader/FormSubmission.cpp b/Source/core/loader/FormSubmission.cpp
index 178a996bc763acb3abfd5f022db45241dbde6af4..dc6a9eef4b269b97f193282dda2e7cebfd3973d9 100644
--- a/Source/core/loader/FormSubmission.cpp
+++ b/Source/core/loader/FormSubmission.cpp
@@ -140,7 +140,7 @@ void FormSubmission::Attributes::copyFrom(const Attributes& other)
     m_acceptCharset = other.m_acceptCharset;
 }
 
-inline FormSubmission::FormSubmission(Method method, const KURL& action, const String& target, const String& contentType, PassRefPtr<FormState> state, PassRefPtr<FormData> data, const String& boundary, PassRefPtr<Event> event)
+inline FormSubmission::FormSubmission(Method method, const KURL& action, const AtomicString& target, const String& contentType, PassRefPtr<FormState> state, PassRefPtr<FormData> data, const String& boundary, PassRefPtr<Event> event)
     : m_method(method)
     , m_action(action)
     , m_target(target)
@@ -238,7 +238,7 @@ PassRefPtr<FormSubmission> FormSubmission::create(HTMLFormElement* form, const A
 
     formData->setIdentifier(generateFormDataIdentifier());
     formData->setContainsPasswordData(containsPasswordData);
-    String targetOrBaseTarget = copiedAttributes.target().isEmpty() ? document.baseTarget() : copiedAttributes.target();
+    AtomicString targetOrBaseTarget = copiedAttributes.target().isEmpty() ? document.baseTarget() : copiedAttributes.target();
     RefPtr<FormState> formState = FormState::create(form, formValues, &document, trigger);
     return adoptRef(new FormSubmission(copiedAttributes.method(), actionURL, targetOrBaseTarget, encodingType, formState.release(), formData.release(), boundary, event));
 }