drive: Fix a crash caused by an empty edit URL

chrome/browser/chromeos/gdata/drive_file_system.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 "chrome/browser/chromeos/gdata/drive_file_system.h"
 
 #include <set>
 #include <utility>
 
 #include "base/bind.h"
@@ skipping 1209 matching lines @@
                  callback,
                  file_path,
                  dir_path));
 }
 
 void DriveFileSystem::Remove(const FilePath& file_path,
     bool is_recursive,
     const FileOperationCallback& callback) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI) ||
          BrowserThread::CurrentlyOn(BrowserThread::IO));
+  DCHECK(!callback.is_null());
+
   RunTaskOnUIThread(base::Bind(&DriveFileSystem::RemoveOnUIThread,
                                ui_weak_ptr_,
                                file_path,
                                CreateRelayCallback(callback)));
 }
 
 void DriveFileSystem::RemoveOnUIThread(
     const FilePath& file_path,
     const FileOperationCallback& callback) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+  DCHECK(!callback.is_null());
 
   // Get the edit URL of an entry at |file_path|.
   resource_metadata_->GetEntryInfoByPath(
       file_path,
       base::Bind(
           &DriveFileSystem::RemoveOnUIThreadAfterGetEntryInfo,
           ui_weak_ptr_,
           callback));
 }
 
 void DriveFileSystem::RemoveOnUIThreadAfterGetEntryInfo(
     const FileOperationCallback& callback,
     DriveFileError error,
     scoped_ptr<DriveEntryProto> entry_proto) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+  DCHECK(!callback.is_null());
 
   if (error != DRIVE_FILE_OK) {
-    if (!callback.is_null()) {
-      base::MessageLoopProxy::current()->PostTask(
-          FROM_HERE, base::Bind(callback, error));
-    }
+    callback.Run(error);
+    return;
+  }
+  DCHECK(entry_proto.get());
+
+  // The edit URL can be empty for some reason.
+  if (entry_proto->edit_url().empty()) {
+    callback.Run(DRIVE_FILE_ERROR_NOT_FOUND);
     return;
   }
 
-  DCHECK(entry_proto.get());
   drive_service_->DeleteDocument(
       GURL(entry_proto->edit_url()),
       base::Bind(&DriveFileSystem::RemoveResourceLocally,
                  ui_weak_ptr_,
                  callback,
                  entry_proto->resource_id()));
 }
 
 void DriveFileSystem::CreateDirectory(
     const FilePath& directory_path,
@@ skipping 1157 matching lines @@
 
   callback.Run(error);
 }
 
 void DriveFileSystem::RemoveResourceLocally(
     const FileOperationCallback& callback,
     const std::string& resource_id,
     GDataErrorCode status,
     const GURL& /* document_url */) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+  DCHECK(!callback.is_null());
 
   DriveFileError error = util::GDataToDriveFileError(status);
   if (error != DRIVE_FILE_OK) {
-    if (!callback.is_null())
-      callback.Run(error);
+    callback.Run(error);
     return;
   }
 
   resource_metadata_->RemoveEntryFromParent(
       resource_id,
       base::Bind(&DriveFileSystem::OnDirectoryChangeFileMoveCallback,
                  ui_weak_ptr_,
                  callback));
 
   cache_->RemoveOnUIThread(resource_id, CacheOperationCallback());
@@ skipping 848 matching lines @@
     return;
   }
 
   PlatformFileInfoProto entry_file_info;
   DriveEntry::ConvertPlatformFileInfoToProto(*file_info, &entry_file_info);
   *entry_proto->mutable_file_info() = entry_file_info;
   callback.Run(DRIVE_FILE_OK, entry_proto.Pass());
 }
 
 }  // namespace gdata