Update usage of GetOffTheRecordProfile in Platform Apps.

Profile API is being updated (issue 1033903) and the usage of
GetOffTheRecordProfile without argument is getting deprecated. Use cases
of this call that only refer to incognito or guest mode can use
GetPrimaryOTRProfile() instead.

All calls to this function in c/b/apps/platform_apps/* are updated.
This CL does not make any behavioral changes.

Bug: 1060940
Change-Id: I3b7c0abc5487711936a028549c21b28b8cc50fc0
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2135751Reviewed-by: Dominick Ng <dominickn@chromium.org>
Commit-Queue: Ramin Halavati <rhalavati@chromium.org>
Cr-Commit-Position: refs/heads/master@{#758737}

chrome/browser/apps/platform_apps/app_browsertest.cc

@@ -1238,7 +1238,7 @@ IN_PROC_BROWSER_TEST_F(PlatformAppIncognitoBrowserTest,
   const Extension* file_manager = extension_registry()->GetExtensionById(
       "hhaomjibdihmijegdhdafkllkbggdgoj", ExtensionRegistry::ENABLED);
   ASSERT_TRUE(file_manager != NULL);
-  Profile* incognito_profile = profile()->GetOffTheRecordProfile();
+  Profile* incognito_profile = profile()->GetPrimaryOTRProfile();
   ASSERT_TRUE(incognito_profile != NULL);
 
   // Wait until the file manager has had a chance to register its listener