Add GetURLForBrowserTab method to the external file system backend.

chrome/browser/chromeos/fileapi/file_system_backend_delegate.h

Index: chrome/browser/chromeos/fileapi/file_system_backend_delegate.h
diff --git a/chrome/browser/chromeos/fileapi/file_system_backend_delegate.h b/chrome/browser/chromeos/fileapi/file_system_backend_delegate.h
index b11c86a5ddefea8b979f70f08bffa79c3e15430d..ffc892be1447d81eedd4add92cb7282ef2d596fb 100644
--- a/chrome/browser/chromeos/fileapi/file_system_backend_delegate.h
+++ b/chrome/browser/chromeos/fileapi/file_system_backend_delegate.h
@@ -6,9 +6,12 @@
 #define CHROME_BROWSER_CHROMEOS_FILEAPI_FILE_SYSTEM_BACKEND_DELEGATE_H_
 
 #include "base/basictypes.h"
+#include "base/callback_forward.h"
 #include "base/memory/scoped_ptr.h"
 #include "webkit/common/fileapi/file_system_types.h"
 
+class GURL;
+
 namespace base {
 class Time;
 }  // namespace base
@@ -24,6 +27,7 @@ class WatcherManager;
 
 namespace storage {
 class FileStreamReader;
+typedef base::Callback<void(const GURL&)> URLCallback;

[mtomasz, 2014/09/04 06:18:51]

nit: This is already declared in webkit/browser/fileapi/file_system_backend.h.

Shall we add an include instead?

[hirono, 2014/09/04 07:15:38]

Done.

 }  // namespace storage
 
 namespace chromeos {
@@ -55,6 +59,13 @@ class FileSystemBackendDelegate {
   // stay valid until shutdown.
   virtual storage::WatcherManager* GetWatcherManager(
       const storage::FileSystemURL& url) = 0;
+
+  // Called from FileSystemBackend::GetRedirectURLForBrowserTab.  Please ensure
+  // that the returned URL is secure. The URL is to be redirected to and opened
+  // in a browser tab.

[mtomasz, 2014/09/04 06:18:51]

nit: Actually not only browser tab. It can be also opened in <img>, <video> in
apps, extensions, as well as via XmlHttpRequest. Right?

If so, then maybe GetRedirectURLForContents? WDYT?

[hirono, 2014/09/04 07:15:38]

Done.

+  virtual void GetRedirectURLForBrowserTab(
+      const storage::FileSystemURL& url,
+      const storage::URLCallback& callback) = 0;
 };
 
 }  // namespace chromeos