Do not crash while saving file using an extension. (uplift to 1.70.x) (…

…#25705)

Uplift of #25702 (squashed) to release

browser/ui/brave_browser.cc

@@ -152,7 +152,7 @@ void BraveBrowser::RunFileChooser(
     // something doesn't reach here. They show 'select file dialog' from
     // DownloadFilePicker::DownloadFilePicker directly.
     // https://source.chromium.org/chromium/chromium/src/+/main:third_party/blink/public/mojom/choosers/file_chooser.mojom;l=27;drc=047c7dc4ee1ce908d7fea38ca063fa2f80f92c77
-
+    CHECK(render_frame_host);
     new_params->title = brave::GetFileSelectTitle(
         content::WebContents::FromRenderFrameHost(render_frame_host),
         render_frame_host->GetLastCommittedOrigin(),

browser/ui/brave_file_select_utils.cc

@@ -52,6 +52,7 @@ std::u16string GetFileSelectTitle(content::WebContents* web_contents,
   // TODO(sko) It's hard to test this behavior is in sync at this moment. Even
   // upstream tests aren't covering this. Need to figure out how we can test
   // extension and isolated web app case.
+  CHECK(web_contents);
   Profile* profile =
       Profile::FromBrowserContext(web_contents->GetBrowserContext());
 

chromium_src/chrome/browser/download/download_file_picker.cc

@@ -21,6 +21,9 @@ std::u16string GetTitle(content::RenderFrameHost* render_frame_host,
 #if BUILDFLAG(IS_ANDROID)
   return original_title;
 #else
+  if (!render_frame_host) {
+    return original_title;
+  }
   return brave::GetFileSelectTitle(
       content::WebContents::FromRenderFrameHost(render_frame_host),
       render_frame_host->GetLastCommittedOrigin(),