ShortcutManager constructor: Added DCHECK for UI thread.

chrome/test/base/testing_profile.cc

Index: chrome/test/base/testing_profile.cc
diff --git a/chrome/test/base/testing_profile.cc b/chrome/test/base/testing_profile.cc
index 3d9511da7f89dafb7b66d242aaf93e12a123a89b..f0240b500a16200fb7fb8ab539c6f705a38d6a24 100644
--- a/chrome/test/base/testing_profile.cc
+++ b/chrome/test/base/testing_profile.cc
@@ -283,6 +283,11 @@ void TestingProfile::CreateTempProfileDir() {
 }
 
 void TestingProfile::Init() {
+  // If threads have been initialized, we should be on the UI thread.
+  DCHECK(
+      !content::BrowserThread::IsWellKnownThread(content::BrowserThread::UI) ||
+      content::BrowserThread::CurrentlyOn(content::BrowserThread::UI));
+
   // Normally this would happen during browser startup, but for tests
   // we need to trigger creation of Profile-related services.
   ChromeBrowserMainExtraPartsProfiles::