Get generate_dump compiling on Windows

tools/tool_support.h

 // Copyright 2014 The Crashpad Authors. All rights reserved.
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
 // You may obtain a copy of the License at
 //
 //     http://www.apache.org/licenses/LICENSE-2.0
 //
 // Unless required by applicable law or agreed to in writing, software
 // distributed under the License is distributed on an "AS IS" BASIS,
 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
 #ifndef CRASHPAD_TOOLS_TOOL_SUPPORT_H_
 #define CRASHPAD_TOOLS_TOOL_SUPPORT_H_
 
 #include <string>
 
 #include "base/basictypes.h"
 #include "base/files/file_path.h"
+#include "base/strings/string_piece.h"
 #include "build/build_config.h"
 
 namespace crashpad {
 
 //! \brief Common functions used by command line tools.
 class ToolSupport {
  public:
   //! \brief Handles `--version`.
   //!
   //! \param[in] me The tool’s name, the basename of `argv[0]`.
@@ skipping 14 matching lines @@
   //! \copydoc Version
   static void Version(const std::string& me);
 
   //! \copydoc UsageTail
   static void UsageTail(const std::string& me);
 
   //! \copydoc UsageHint
   static void UsageHint(const std::string& me, const char* hint);
 #endif  // OS_POSIX
 
+#if defined(OS_WIN) || DOXYGEN
+  //! \brief Converts \a argv `wchar_t` UTF-16 to UTF-8, and passes onwards to a
+  //!     UTF-8 entry point.
+  //!
+  //! \return The return value of \a entry.
+  static int Wmain(int argc, wchar_t* argv[], int (*entry)(int, char*[]));
+#endif  // OS_WIN
+
+  //! \brief Converts a command line argument to the string type suitable for
+  //!     base::FilePath.
+  //!
+  //! On POSIX, this is a no-op. On Windows, assumes that Wmain() was used, and
+  //! the input argument was converted from UTF-16 in a `wchar_t*` to UTF-8 in a
+  //! `char*`. This undoes that transformation.
+  //!
+  //! \sa Wmain()
+  static base::FilePath::StringType CommandLineArgumentToFilePathStringType(
+      const base::StringPiece& arg);
+
  private:
   DISALLOW_IMPLICIT_CONSTRUCTORS(ToolSupport);
 };
 
 }  // namespace crashpad
 
 #endif  // CRASHPAD_TOOLS_TOOL_SUPPORT_H_