Move FilePathWatcher class from browser/... to common/...

chrome/browser/policy/file_based_policy_loader.cc

Index: chrome/browser/policy/file_based_policy_loader.cc
diff --git a/chrome/browser/policy/file_based_policy_loader.cc b/chrome/browser/policy/file_based_policy_loader.cc
index cc89d13e684f4145933fe20b05ac1778cdfbefe7..738d6802b754e4feb38423fd5976a47462c3a545 100644
--- a/chrome/browser/policy/file_based_policy_loader.cc
+++ b/chrome/browser/policy/file_based_policy_loader.cc
@@ -4,6 +4,8 @@
 
 #include "chrome/browser/policy/file_based_policy_loader.h"
 
+#include "content/browser/browser_thread.h"
+
 namespace {
 
 // Amount of time we wait for the files on disk to settle before trying to load
@@ -93,8 +95,10 @@ void FileBasedPolicyLoader::InitOnFileThread() {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::FILE));
   watcher_.reset(new FilePathWatcher);
   if (!config_file_path().empty() &&
-      !watcher_->Watch(config_file_path(),
-                       new FileBasedPolicyWatcherDelegate(this))) {
+      !watcher_->Watch(
+          config_file_path(),
+          new FileBasedPolicyWatcherDelegate(this),
+          BrowserThread::GetMessageLoopProxyForThread(BrowserThread::UI))) {
     OnError();
   }