Chromium side patch for DB support on Linux.

base/platform_file_posix.cc

Index: base/platform_file_posix.cc
===================================================================
--- base/platform_file_posix.cc	(revision 24791)
+++ base/platform_file_posix.cc	(working copy)
@@ -52,6 +52,10 @@
         *created = false;
     } else {
       open_flags |= O_CREAT;
+      if (flags & PLATFORM_FILE_EXCLUSIVE_READ ||
+          flags & PLATFORM_FILE_EXCLUSIVE_WRITE) {
+        open_flags |= O_EXCL;   // together with O_CREAT implies O_NOFOLLOW
+      }
       descriptor = open(WideToUTF8(name).c_str(), open_flags,
                         S_IRUSR | S_IWUSR);
       if (created && descriptor > 0)
@@ -59,7 +63,15 @@
     }
   }
 
+  if ((descriptor > 0) && (flags & PLATFORM_FILE_DELETE_ON_CLOSE)) {
+    unlink(WideToUTF8(name).c_str());
+  }
+
   return descriptor;
 }
 
+bool ClosePlatformFile(PlatformFile file) {
+  return close(file);
+}
+
 }  // namespace base