Start consolidating cross-port file selection code into ui/base/dialogs.

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 9c11232eaa575021cab34cab52b7eb31ba6ece12..67c886dab79bef3ca29b31b4a70b14af50047fc4 100644
--- a/chrome/browser/file_select_helper.cc
+++ b/chrome/browser/file_select_helper.cc
@@ -16,6 +16,7 @@
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/ui/browser.h"
 #include "chrome/browser/ui/browser_list.h"
+#include "chrome/browser/ui/chrome_select_file_policy.h"
 #include "content/public/browser/notification_details.h"
 #include "content/public/browser/notification_source.h"
 #include "content/public/browser/notification_types.h"
@@ -371,8 +372,8 @@ void FileSelectHelper::RunFileChooserOnUIThread(
     return;
   }
 
-  if (!select_file_dialog_.get())
-    select_file_dialog_ = SelectFileDialog::Create(this);
+  select_file_dialog_ = SelectFileDialog::Create(
+      this, new ChromeSelectFilePolicy(web_contents_));
 
   switch (params.mode) {
     case FileChooserParams::Open:
@@ -405,7 +406,6 @@ void FileSelectHelper::RunFileChooserOnUIThread(
       select_file_types_.get(),
       select_file_types_.get() ? 1 : 0,  // 1-based index.
       FILE_PATH_LITERAL(""),
-      web_contents_,
       owning_window,
 #if defined(OS_ANDROID)
       const_cast<content::FileChooserParams*>(&params));