Grant read permission for the non-native files passed as a result of file chooser.

The property of FileChooserFileInfo#file_system_url is newly added for handling non-native files in Chrome OS.

BUG=126902
TEST=None

Review URL: https://codereview.chromium.org/655153002

Cr-Commit-Position: refs/heads/master@{#299847}

content/browser/renderer_host/render_view_host_impl.cc

@@ -734,6 +734,10 @@ void RenderViewHostImpl::SetInitialFocus(bool reverse) {
 void RenderViewHostImpl::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 (size_t i = 0; i < files.size(); ++i) {
     const content::FileChooserFileInfo& file = files[i];
@@ -744,6 +748,12 @@ void RenderViewHostImpl::FilesSelectedInChooser(
       ChildProcessSecurityPolicyImpl::GetInstance()->GrantReadFile(
           GetProcess()->GetID(), file.file_path);
     }
+    if (file.file_system_url.is_valid()) {
+      ChildProcessSecurityPolicyImpl::GetInstance()->GrantReadFileSystem(
+          GetProcess()->GetID(),
+          file_system_context->CrackURL(file.file_system_url)
+          .mount_filesystem_id());
+    }
   }
   Send(new ViewMsg_RunFileChooserResponse(GetRoutingID(), files));
 }