Add a comment about ownership of the drive integration pointer

Comment only change.

No-Try: true
Bug: 833834
Change-Id: I17bfb7a9ba9c9146a1c5496001b368f00a627f55
Reviewed-on: https://chromium-review.googlesource.com/1034414Reviewed-by: Stuart Langley <slangley@chromium.org>
Commit-Queue: Noel Gordon <noel@chromium.org>
Cr-Commit-Position: refs/heads/master@{#554683}

chrome/browser/chromeos/file_manager/file_manager_browsertest_base.h

@@ -55,7 +55,7 @@ class FileManagerBrowserTestBase : public ExtensionApiTest {
 
  private:
   // Called during setup if needed, to create a drive integration service for
-  // the given Profile |profile|.
+  // the given |profile|. Caller owns the return result.
   drive::DriveIntegrationService* CreateDriveIntegrationService(
       Profile* profile);