Exclude files from FileSelectChooser if they can't convert to WebStrings.

content/renderer/render_frame_impl.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 "content/renderer/render_frame_impl.h"
 
 #include <map>
 #include <string>
 #include <utility>
 #include <vector>
@@ skipping 5737 matching lines @@
   suppress_further_dialogs_ = true;
 }
 
 void RenderFrameImpl::OnFileChooserResponse(
     const std::vector<content::FileChooserFileInfo>& files) {
   // This could happen if we navigated to a different page before the user
   // closed the chooser.
   if (file_chooser_completions_.empty())
     return;
 
+  // Exclude files whose paths can't be converted into WebStrings.  Blink won't
+  // be able to handle these, and the browser process would kill the renderer
+  // when it claims to have chosen an empty file path.
+  std::vector<content::FileChooserFileInfo> filtered_files;
+  for (const auto& file : files) {
+    if (!blink::FilePathToWebString(file.file_path).IsEmpty())
+      filtered_files.push_back(file);
+  }
+
   // Convert Chrome's SelectedFileInfo list to WebKit's.
   WebVector<blink::WebFileChooserCompletion::SelectedFileInfo> selected_files(
-      files.size());
-  for (size_t i = 0; i < files.size(); ++i) {
+      filtered_files.size());
+  for (size_t i = 0; i < filtered_files.size(); ++i) {
     blink::WebFileChooserCompletion::SelectedFileInfo selected_file;
-    selected_file.path = blink::FilePathToWebString(files[i].file_path);
-    selected_file.display_name =
-        blink::FilePathToWebString(base::FilePath(files[i].display_name));
-    if (files[i].file_system_url.is_valid()) {
-      selected_file.file_system_url = files[i].file_system_url;
-      selected_file.length = files[i].length;
-      selected_file.modification_time = files[i].modification_time.ToDoubleT();
-      selected_file.is_directory = files[i].is_directory;
+    selected_file.path =
+        blink::FilePathToWebString(filtered_files[i].file_path);

[asanka, 2017/04/20 03:05:11]

Nit: Why not skip test with selected_file.path.IsEmpty() here and skip?

[Charlie Reis, 2017/04/20 19:00:38]

Heh, I did try that at first.  :)  AFAICT, WebVector doesn't have any way to
resize or build up arrays of unknown size.  You have to declare its size in
advance and any gaps left over have default constructed objects.

However, Nick pointed out that we could only do an extra pass in the rare case
that we didn't copy over every extra element.  I've switched to that approach. 
(Thanks!)

+    selected_file.display_name = blink::FilePathToWebString(
+        base::FilePath(filtered_files[i].display_name));
+    if (filtered_files[i].file_system_url.is_valid()) {
+      selected_file.file_system_url = filtered_files[i].file_system_url;
+      selected_file.length = filtered_files[i].length;
+      selected_file.modification_time =
+          filtered_files[i].modification_time.ToDoubleT();
+      selected_file.is_directory = filtered_files[i].is_directory;
     }
     selected_files[i] = selected_file;
   }
 
   if (file_chooser_completions_.front()->completion) {
     file_chooser_completions_.front()->completion->DidChooseFile(
         selected_files);
   }
   file_chooser_completions_.pop_front();
 
@@ skipping 1194 matching lines @@
       policy(info.default_policy),
       replaces_current_history_item(info.replaces_current_history_item),
       history_navigation_in_new_child_frame(
           info.is_history_navigation_in_new_child_frame),
       client_redirect(info.is_client_redirect),
       cache_disabled(info.is_cache_disabled),
       form(info.form),
       source_location(info.source_location) {}
 
 }  // namespace content