Prefer System Flash over non-local component updated Flash.

base/files/file_util_win.cc

 // 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"
 
 #include <windows.h>
 #include <io.h>
 #include <psapi.h>
 #include <shellapi.h>
@@ skipping 541 matching lines @@
   bool success = false;
   HANDLE cp = GetCurrentProcess();
   if (::GetMappedFileNameW(cp, file_view, mapped_file_path, kMaxPathLength)) {
     *nt_path = FilePath(mapped_file_path);
     success = true;
   }
   ::UnmapViewOfFile(file_view);
   return success;
 }
 
+bool IsOnNetworkDrive(const base::FilePath& path) {
+  win::ScopedHandle handle(
+      ::CreateFileW(path.value().c_str(),
+                    0,
+                    FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE,

[Lei Zhang, 2016/04/15 21:16:36]

Do you need write and delete permissions?

[Will Harris, 2016/04/15 21:30:31]

These aren't file reading permissions these are file sharing permissions, it's a
Windows-ism which basically is to do with other processes that might have the
file open and yet still being able to read it.

I should probably add a GENERIC_READ in there though. true.

+                    NULL,
+                    OPEN_EXISTING,
+                    FILE_FLAG_BACKUP_SEMANTICS,  // Needed to open directory.
+                    NULL));
+
+  FILE_REMOTE_PROTOCOL_INFO remote_proto_info = {0};
+
+  // If able to get network information, then the file is on a network.
+  if (::GetFileInformationByHandleEx(handle.Get(),

[Lei Zhang, 2016/04/15 21:16:36]

Just return !!::GetFoo(...) ?

[Will Harris, 2016/04/15 21:30:31]

Acknowledged.

+                                     FileRemoteProtocolInfo, &remote_proto_info,
+                                     sizeof(remote_proto_info))) {
+    return true;

[cpu_(ooo_6.6-7.5), 2016/04/15 20:55:33]

seems reasonable...  but what if the file does not exist?

[Will Harris, 2016/04/15 21:15:06]

files that don't exist are not on a network drive... :)

+  }
+
+  return false;
+}
+
 // TODO(rkc): Work out if we want to handle NTFS junctions here or not, handle
 // them if we do decide to.
 bool IsLink(const FilePath& file_path) {
   return false;
 }
 
 bool GetFileInfo(const FilePath& file_path, File::Info* results) {
   ThreadRestrictions::AssertIOAllowed();
 
   WIN32_FILE_ATTRIBUTE_DATA attr;
@@ skipping 251 matching lines @@
     // Like Move, this function is not transactional, so we just
     // leave the copied bits behind if deleting from_path fails.
     // If to_path exists previously then we have already overwritten
     // it by now, we don't get better off by deleting the new bits.
   }
   return false;
 }
 
 }  // namespace internal
 }  // namespace base