Do not open a downloaded file with generic file handler.

chrome/browser/chromeos/file_manager/open_util.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/file_manager/open_util.h"
 
 #include "base/bind.h"
 #include "base/files/file_path.h"
 #include "base/logging.h"
 #include "base/strings/utf_string_conversions.h"
@@ skipping 85 matching lines @@
   file_urls.push_back(url);
 
   std::vector<file_tasks::FullTaskDescriptor> tasks;
   file_tasks::FindAllTypesOfTasks(
       profile,
       drive::util::GetDriveAppRegistryByProfile(profile),
       path_mime_set,
       file_urls,
       &tasks);
 
-  if (tasks.empty()) {
-    callback.Run(false);
-    return;
-  }
-
-  const file_tasks::FullTaskDescriptor* chosen_task = &tasks[0];
-  for (size_t i = 0; i < tasks.size(); ++i) {
-    if (tasks[i].is_default()) {
-      chosen_task = &tasks[i];
-      break;
+  // Select a default handler. If a default handler is not available, select
+  // a non-generic file handler.
+  const file_tasks::FullTaskDescriptor* chosen_task = nullptr;
+  for (const auto& task : tasks) {
+    if (!task.is_generic_file_handler()) {
+      chosen_task = &task;
+      if (task.is_default())
+        break;
     }
   }
 
-  ExecuteFileTaskForUrl(profile, chosen_task->task_descriptor(), url);
-  callback.Run(true);
+  if (chosen_task != nullptr) {
+    ExecuteFileTaskForUrl(profile, chosen_task->task_descriptor(), url);
+    callback.Run(true);
+  } else {
+    callback.Run(false);
+  }
 }
 
 // Opens the file specified by |url| by finding and executing a file task for
 // the file. In case of success, calls |callback| with true. Otherwise the
 // returned value is false.
 void OpenFile(Profile* profile,
               const base::FilePath& path,
               const GURL& url,
               const base::Callback<void(bool)>& callback) {
   extensions::app_file_handler_util::GetMimeTypeForLocalPath(
@@ skipping 73 matching lines @@
   GURL url;
   if (!ConvertPath(profile, file_path, &url))
     return;
 
   // This action changes the selection so we do not reuse existing tabs.
   OpenFileManagerWithInternalActionId(profile, url, "select");
 }
 
 }  // namespace util
 }  // namespace file_manager