PPAPI: Add PluginPrivateFileSystem

ppapi/proxy/isolated_file_system_private_resource.cc

 // Copyright 2013 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 "ppapi/proxy/isolated_file_system_private_resource.h"
 
 #include "base/bind.h"
 #include "base/logging.h"
 #include "ppapi/c/pp_errors.h"
 #include "ppapi/c/pp_file_info.h"
@@ skipping 29 matching lines @@
 }
 
 int32_t IsolatedFileSystemPrivateResource::Open(
     PP_Instance /* unused */,
     PP_IsolatedFileSystemType_Private type,
     PP_Resource* file_system_resource,
     scoped_refptr<TrackedCallback> callback) {
   if (!file_system_resource)
     return PP_ERROR_BADARGUMENT;
 
+#ifndef OS_CHROMEOS
+  // PluginPrivate filesystem is supported only on ChromeOS.

[dmichael (off chromium), 2013/11/15 17:42:44]

Thanks. I think we want to actually check this on the host side, though.
Messages from the plugin can be forged (especially in NaCl). I don't think
there's a security concern with this particular API, but we shouldn't ever trust
the plugin code.

BTW: Does the backend stuff make any assumptions about it being ChromeOS only?
Justin and I were just talking, and we could arguably make this a stable API
some day. It won't be as useful on other platforms, but we still *could* do it
if the backend supports it.

[nhiroki, 2013/11/18 11:21:17]

Good to know. I considered this closely, and I think the backend does not make
any assumptions about ChromeOS, so we can remove this check (and removed).

+  if (type == PP_ISOLATEDFILESYSTEMTYPE_PRIVATE_PLUGINPRIVATE) {
+    LOG(WARNING) << "PluginPrivate filesystem is not supported.";
+    return PP_ERROR_NOTSUPPORTED;
+  }
+#endif
+
   Call<PpapiPluginMsg_IsolatedFileSystem_BrowserOpenReply>(BROWSER,
       PpapiHostMsg_IsolatedFileSystem_BrowserOpen(type),
       base::Bind(&IsolatedFileSystemPrivateResource::OnBrowserOpenComplete,
                  this, type, file_system_resource, callback));
   return PP_OK_COMPLETIONPENDING;
 }
 
 void IsolatedFileSystemPrivateResource::OnBrowserOpenComplete(
     PP_IsolatedFileSystemType_Private type,
     PP_Resource* file_system_resource,
@@ skipping 12 matching lines @@
       connection(), pp_instance(), PP_FILESYSTEMTYPE_ISOLATED);
   *file_system_resource = fs->GetReference();
   if (*file_system_resource == 0)
     callback->Run(PP_ERROR_FAILED);
   fs->InitIsolatedFileSystem(
       fsid, type, base::Bind(&RunTrackedCallback, callback));
 }
 
 }  // namespace proxy
 }  // namespace ppapi