[Sync] Creating sync_sessions component, moving revisit logic.

components/sync_sessions/revisit/offset_tab_matcher.cc

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#include "components/sync_driver/revisit/offset_tab_matcher.h"
+#include "components/sync_sessions/revisit/offset_tab_matcher.h"
+
+#include <algorithm>
 
 #include "base/metrics/histogram_macros.h"
 #include "base/metrics/sparse_histogram.h"
 #include "components/sessions/core/serialized_navigation_entry.h"
 
-namespace sync_driver {
+namespace sync_sessions {
 
 namespace {
 
 // This is an upper bound of the max size of positive offset we will emit
 // correct metrics for. Anything larger than this will be clamped to this value.
 // This value doesn't exactly correspond to what we actually expect, this value
 // is currently larger than expected. This value is more for the safety of our
 // sparse histogram usage. It is assumed that the max negative offset is
 // symmetrical and can be found by taking the negative of this value.
 const int kMaxOffset = 10;
@@ skipping 47 matching lines @@
     UMA_HISTOGRAM_ENUMERATION("Sync.PageRevisitNavigationMatchTransition",
                               transition,
                               PageVisitObserver::kTransitionTypeLast);
   }
 }
 
 int OffsetTabMatcher::Clamp(const int input, const int lower, const int upper) {
   return std::max(lower, std::min(upper, input));
 }
 
-}  // namespace sync_driver
+}  // namespace sync_sessions