Refactor "IsUnderDriveMountPoint" in v2 app code for generalization to non-Drive volumes.

chrome/browser/extensions/api/file_system/file_system_api.h

Index: chrome/browser/extensions/api/file_system/file_system_api.h
diff --git a/chrome/browser/extensions/api/file_system/file_system_api.h b/chrome/browser/extensions/api/file_system/file_system_api.h
index 7aee4e5c7797e52b85ef5d4267e29797c4c6ff52..df4e6627f2c76debf11da9543eff6f8c4e7902a2 100644
--- a/chrome/browser/extensions/api/file_system/file_system_api.h
+++ b/chrome/browser/extensions/api/file_system/file_system_api.h
@@ -157,12 +157,13 @@ class FileSystemChooseEntryFunction : public FileSystemEntryFunction {
   void FilesSelected(const std::vector<base::FilePath>& path);
   void FileSelectionCanceled();
 
-  // Check if the chosen directory is or is an ancestor of a sensitive
-  // directory. If so, show a dialog to confirm that the user wants to open the
-  // directory. Calls OnDirectoryAccessConfirmed if the directory isn't
-  // sensitive or the user chooses to open it. Otherwise, calls
-  // FileSelectionCanceled.
+  // Check if |check_path|, the canonicalized form of the chosen directory
+  // |paths|, is or is an ancestor of a sensitive directory. If so, show a
+  // dialog to confirm that the user wants to open the directory.
+  // Calls OnDirectoryAccessConfirmed if the directory isn't sensitive or the
+  // user chooses to open it. Otherwise, calls FileSelectionCanceled.
   void ConfirmDirectoryAccessOnFileThread(
+      const base::FilePath& check_path,
       const std::vector<base::FilePath>& paths,
       content::WebContents* web_contents);
   void OnDirectoryAccessConfirmed(const std::vector<base::FilePath>& paths);