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

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

Index: chrome/browser/extensions/api/file_system/file_system_api.cc
diff --git a/chrome/browser/extensions/api/file_system/file_system_api.cc b/chrome/browser/extensions/api/file_system/file_system_api.cc
index fee90cba6dd704b109cad4d4ce2121a8485757d8..5e135a2175d92e35266fa0a70a32d814442b8ebb 100644
--- a/chrome/browser/extensions/api/file_system/file_system_api.cc
+++ b/chrome/browser/extensions/api/file_system/file_system_api.cc
@@ -50,7 +50,7 @@
 #endif
 
 #if defined(OS_CHROMEOS)
-#include "chrome/browser/chromeos/drive/file_system_util.h"
+#include "chrome/browser/chromeos/file_manager/filesystem_api_util.h"
 #endif
 
 using apps::SavedFileEntry;
@@ -680,13 +680,24 @@ void FileSystemChooseEntryFunction::FilesSelected(
     }
     content::WebContents* web_contents = app_window->web_contents();
 
+    DCHECK_EQ(paths.size(), 1u);
+    std::vector<base::FilePath> check_paths;
+#if defined(OS_CHROMEOS)
+    check_paths.push_back(
+        file_manager::util::IsUnderSpecialPath(GetProfile(), paths[0])
+            ? paths[0]
+            : base::MakeAbsoluteFilePath(paths[0]));
+#else
+    check_paths.push_back(base::MakeAbsoluteFilePath(paths[0]));
+#endif
+
     content::BrowserThread::PostTask(
         content::BrowserThread::FILE,
         FROM_HERE,
         base::Bind(
             &FileSystemChooseEntryFunction::ConfirmDirectoryAccessOnFileThread,
             this,
-            paths,
+            check_paths,
             web_contents));
     return;
   }
@@ -703,13 +714,8 @@ void FileSystemChooseEntryFunction::ConfirmDirectoryAccessOnFileThread(
     const std::vector<base::FilePath>& paths,
     content::WebContents* web_contents) {
   DCHECK_EQ(paths.size(), 1u);
-#if defined(OS_CHROMEOS)
-  const base::FilePath path =
-      drive::util::IsUnderDriveMountPoint(paths[0]) ? paths[0] :
-          base::MakeAbsoluteFilePath(paths[0]);
-#else
-  const base::FilePath path = base::MakeAbsoluteFilePath(paths[0]);
-#endif
+  const base::FilePath& path = paths[0];
+
   if (path.empty()) {
     content::BrowserThread::PostTask(
         content::BrowserThread::UI,