Fix file chooser on ChromeOS.

chrome/browser/file_select_helper.cc

Index: chrome/browser/file_select_helper.cc
diff --git a/chrome/browser/file_select_helper.cc b/chrome/browser/file_select_helper.cc
index 514ea628df2b9460b050acddc1cd07c3a0b6e54e..46c553886602bd4a2d376d238183f9fd18a02fe4 100644
--- a/chrome/browser/file_select_helper.cc
+++ b/chrome/browser/file_select_helper.cc
@@ -655,12 +655,14 @@ void FileSelectHelper::Observe(int type,
 void FileSelectHelper::RenderFrameHostChanged(
     content::RenderFrameHost* old_host,
     content::RenderFrameHost* new_host) {
-  render_frame_host_ = nullptr;
+  if (old_host == render_frame_host_)
+    render_frame_host_ = nullptr;
 }
 
 void FileSelectHelper::RenderFrameDeleted(
     content::RenderFrameHost* render_frame_host) {
-  render_frame_host_ = nullptr;
+  if (render_frame_host == render_frame_host_)
+    render_frame_host_ = nullptr;
 }
 
 void FileSelectHelper::WebContentsDestroyed() {