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

base/files/file_util_mac.mm

Index: base/files/file_util_mac.mm
diff --git a/base/files/file_util_mac.mm b/base/files/file_util_mac.mm
index 695935a2e31fe162b1690b1b3d28f60c4e09d732..acac8d738ea1d52e68e70be9c7e4357816d72807 100644
--- a/base/files/file_util_mac.mm
+++ b/base/files/file_util_mac.mm
@@ -14,16 +14,15 @@
 #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)