Special-case paths that appear in libs by not prefixing them with -l.

tools/gn/lib_file.h

Index: tools/gn/lib_file.h
diff --git a/tools/gn/lib_file.h b/tools/gn/lib_file.h
new file mode 100644
index 0000000000000000000000000000000000000000..8e471f291cdb6b21289f05d6b314a8b252a81d99
--- /dev/null
+++ b/tools/gn/lib_file.h
@@ -0,0 +1,56 @@
+// Copyright 2015 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 TOOLS_GN_LIB_FILE_H_
+#define TOOLS_GN_LIB_FILE_H_
+
+#include <algorithm>
+#include <string>
+
+#include "base/strings/string_piece.h"
+#include "tools/gn/source_file.h"
+
+// Represents an entry in "libs" list. Can be either a path (a SourceFile) or
+// a library name (a string).
+class LibFile {
+ public:
+  LibFile();
+  explicit LibFile(const base::StringPiece& lib_name);
+  explicit LibFile(const SourceFile& source_file);
+
+  void Swap(LibFile* other);
+  bool is_source_file() const { return name_.empty(); }
+
+  // Returns name, or source_file().value() (whichever is set).
+  const std::string& value() const;
+  const SourceFile& source_file() const;
+
+  bool operator==(const LibFile& other) const {
+    return value() == other.value();
+  }
+  bool operator!=(const LibFile& other) const { return !operator==(other); }
+  bool operator<(const LibFile& other) const { return value() < other.value(); }
+
+ private:
+  std::string name_;
+  SourceFile source_file_;
+};
+
+namespace BASE_HASH_NAMESPACE {
+
+template <>
+struct hash<LibFile> {
+  std::size_t operator()(const LibFile& v) const {
+    hash<std::string> h;
+    return h(v.value());
+  }
+};
+
+}  // namespace BASE_HASH_NAMESPACE
+
+inline void swap(LibFile& lhs, LibFile& rhs) {
+  lhs.Swap(&rhs);
+}
+
+#endif  // TOOLS_GN_LIB_FILE_H_