base::CopyFile can copy *from* Android's content scheme.

base/files/file_util_mac.mm

 // Copyright (c) 2012 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.
 
 #include "base/files/file_util.h"
 
 #import <Foundation/Foundation.h>
 #include <copyfile.h>
 
 #include "base/basictypes.h"
 #include "base/files/file_path.h"
 #include "base/mac/foundation_util.h"
 #include "base/strings/string_util.h"
 #include "base/threading/thread_restrictions.h"
 
 namespace base {
-namespace internal {
 
-bool CopyFileUnsafe(const FilePath& from_path, const FilePath& to_path) {
+bool CopyFile(const FilePath& from_path, const FilePath& to_path) {
   ThreadRestrictions::AssertIOAllowed();
+  if (from_path.ReferencesParent() || to_path.ReferencesParent())
+    return false;
   return (copyfile(from_path.value().c_str(),
                    to_path.value().c_str(), NULL, COPYFILE_DATA) == 0);
 }
 
-}  // namespace internal
-
 bool GetTempDir(base::FilePath* path) {
   NSString* tmp = NSTemporaryDirectory();
   if (tmp == nil)
     return false;
   *path = base::mac::NSStringToFilePath(tmp);
   return true;
 }
 
 FilePath GetHomeDir() {
   NSString* tmp = NSHomeDirectory();
   if (tmp != nil) {
     FilePath mac_home_dir = base::mac::NSStringToFilePath(tmp);
     if (!mac_home_dir.empty())
       return mac_home_dir;
   }
 
   // Fall back on temp dir if no home directory is defined.
   FilePath rv;
   if (GetTempDir(&rv))
     return rv;
 
   // Last resort.
   return FilePath("/tmp");
 }
 
 }  // namespace base