Store SourceLocation in ErrorEvent.

third_party/WebKit/Source/bindings/core/v8/SourceLocation.h

 // Copyright 2016 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.
 
 #ifndef SourceLocation_h
 #define SourceLocation_h
 
 #include "core/CoreExport.h"
 #include "platform/v8_inspector/public/V8StackTrace.h"
 #include "wtf/Forward.h"
@@ skipping 10 matching lines @@
 public:
     // Zero lineNumber and columnNumber mean unknown. Captures current stack trace.
     static PassOwnPtr<SourceLocation> capture(const String& url, unsigned lineNumber, unsigned columnNumber);
 
     // Shortcut when location is unknown. Tries to capture call stack or parsing location if available.
     static PassOwnPtr<SourceLocation> capture(ExecutionContext* = nullptr);
 
     static PassOwnPtr<SourceLocation> fromMessage(v8::Isolate*, v8::Local<v8::Message>, ExecutionContext*);
 
     static PassOwnPtr<SourceLocation> create(const String& url, unsigned lineNumber, unsigned columnNumber, std::unique_ptr<V8StackTrace>, int scriptId = 0);
-    static PassOwnPtr<SourceLocation> createFromNonEmptyV8StackTrace(std::unique_ptr<V8StackTrace>, int scriptId = 0);
     ~SourceLocation();
 
     bool isEmpty() const { return m_url.isNull(); }
-    String url() const { return m_url; }
+    const String& url() const { return m_url; }
     unsigned lineNumber() const { return m_lineNumber; }
     unsigned columnNumber() const { return m_columnNumber; }
     std::unique_ptr<V8StackTrace> takeStackTrace() { return std::move(m_stackTrace); }
     int scriptId() const { return m_scriptId; }
     void toTracedValue(TracedValue*, const char* name) const;
     PassOwnPtr<SourceLocation> clone() const;
 
 private:
     SourceLocation(const String& url, unsigned lineNumber, unsigned columnNumber, std::unique_ptr<V8StackTrace>, int scriptId);
+    static PassOwnPtr<SourceLocation> createFromNonEmptyV8StackTrace(std::unique_ptr<V8StackTrace>, int scriptId);
 
     String m_url;
     unsigned m_lineNumber;
     unsigned m_columnNumber;
     std::unique_ptr<V8StackTrace> m_stackTrace;
     int m_scriptId;
 };
 
 } // namespace blink
 
 #endif // SourceLocation_h