Chromium side patch for DB support on Linux.

base/platform_file.h

Index: base/platform_file.h
===================================================================
--- base/platform_file.h	(revision 24791)
+++ base/platform_file.h	(working copy)
@@ -34,16 +34,19 @@
   PLATFORM_FILE_ASYNC = 256,
   PLATFORM_FILE_TEMPORARY = 512,        // Used on Windows only
   PLATFORM_FILE_HIDDEN = 1024,          // Used on Windows only
-  PLATFORM_FILE_DELETE_ON_CLOSE = 2048  // Used on Windows only
+  PLATFORM_FILE_DELETE_ON_CLOSE = 2048
 };
 
-// Creates or open the given file. If PLATFORM_FILE_OPEN_ALWAYS is used, and
+// Creates or opens the given file. If PLATFORM_FILE_OPEN_ALWAYS is used, and
 // |created| is provided, |created| will be set to true if the file was created
 // or to false in case the file was just opened.
 PlatformFile CreatePlatformFile(const std::wstring& name,
                                 int flags,
                                 bool* created);
 
+// Closes a file handle
+bool ClosePlatformFile(PlatformFile file);
+
 }  // namespace base
 
 #endif  // BASE_PLATFORM_FILE_H_