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

content/browser/frame_host/render_frame_host_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/browser/frame_host/render_frame_host_impl.h"
 
 #include <algorithm>
 #include <utility>
 
 #include "base/bind.h"
@@ skipping 3200 matching lines @@
 
 void RenderFrameHostImpl::FilesSelectedInChooser(
     const std::vector<content::FileChooserFileInfo>& files,
     FileChooserParams::Mode permissions) {
   storage::FileSystemContext* const file_system_context =
       BrowserContext::GetStoragePartition(GetProcess()->GetBrowserContext(),
                                           GetSiteInstance())
           ->GetFileSystemContext();
   // Grant the security access requested to the given files.
   for (const auto& file : files) {
+    // We shouldn't be given a FilePath that can't survive the conversion to a
+    // WebString, which we can approximate with AsUTF8Unsafe.  Blink won't be
+    // able to handle it, and we would kill the renderer when it claims to have
+    // chosen an empty file path.
+    DCHECK(!file.file_path.AsUTF8Unsafe().empty());
+
     if (permissions == FileChooserParams::Save) {
       ChildProcessSecurityPolicyImpl::GetInstance()->GrantCreateReadWriteFile(
           GetProcess()->GetID(), file.file_path);
     } else {
       ChildProcessSecurityPolicyImpl::GetInstance()->GrantReadFile(
           GetProcess()->GetID(), file.file_path);
     }
     if (file.file_system_url.is_valid()) {
       ChildProcessSecurityPolicyImpl::GetInstance()->GrantReadFileSystem(
           GetProcess()->GetID(),
@@ skipping 466 matching lines @@
 }
 
 void RenderFrameHostImpl::ForwardGetInterfaceToRenderFrame(
     const std::string& interface_name,
     mojo::ScopedMessagePipeHandle pipe) {
   GetRemoteInterfaces()->GetInterface(interface_name, std::move(pipe));
 }
 #endif
 
 }  // namespace content