[BrowserSwitcher] Add BrowserSwitcherPrefs class

This class can listen for prefs changes, and pre-compute/convert types
for the BrowserSwitcher prefs. It also checks whether the prefs are
managed or not, and offers getters to conveniently access the prefs.

Change-Id: I64a218f10e30193b8a322c49f1ae08feaf80a128
Reviewed-on: https://chromium-review.googlesource.com/c/1393450
Commit-Queue: Nicolas Ouellet-Payeur <[email protected]>
Reviewed-by: Gabriel Charette <[email protected]>
Reviewed-by: Julian Pastarmov <[email protected]>
Cr-Commit-Position: refs/heads/master@{#619993}
diff --git a/chrome/browser/prefs/browser_prefs.cc b/chrome/browser/prefs/browser_prefs.cc
index 2a8001cf..58dfb84 100644
--- a/chrome/browser/prefs/browser_prefs.cc
+++ b/chrome/browser/prefs/browser_prefs.cc
@@ -757,7 +757,7 @@
 
 #if defined(OS_WIN) || defined(OS_MACOSX) || \
     (defined(OS_LINUX) && !defined(OS_CHROMEOS))
-  browser_switcher::prefs::RegisterProfilePrefs(registry);
+  browser_switcher::BrowserSwitcherPrefs::RegisterProfilePrefs(registry);
 #endif
 
 #if defined(TOOLKIT_VIEWS)