Move CancelableTaskTracker to //base/task/CancelableTaskTracker.

chrome/browser/sessions/base_session_service.cc

Index: chrome/browser/sessions/base_session_service.cc
diff --git a/chrome/browser/sessions/base_session_service.cc b/chrome/browser/sessions/base_session_service.cc
index 7948d1318b636ef947780519f5a7ec7421e10276..a07fd98e8743516a25ec67edc28b319ebfdc6b38 100644
--- a/chrome/browser/sessions/base_session_service.cc
+++ b/chrome/browser/sessions/base_session_service.cc
@@ -43,7 +43,7 @@ void WriteStringToPickle(Pickle& pickle, int* bytes_written, int max_bytes,
 // Helper used by ScheduleGetLastSessionCommands. It runs callback on TaskRunner
 // thread if it's not canceled.
 void RunIfNotCanceled(
-    const CancelableTaskTracker::IsCanceledCallback& is_canceled,
+    const base::CancelableTaskTracker::IsCanceledCallback& is_canceled,
     const BaseSessionService::InternalGetCommandsCallback& callback,
     ScopedVector<SessionCommand> commands) {
   if (is_canceled.Run())
@@ -272,12 +272,13 @@ bool BaseSessionService::ShouldTrackEntry(const GURL& url) {
                               url.host() == chrome::kChromeUIRestartHost));
 }
 
-CancelableTaskTracker::TaskId
-    BaseSessionService::ScheduleGetLastSessionCommands(
+base::CancelableTaskTracker::TaskId
+BaseSessionService::ScheduleGetLastSessionCommands(
     const InternalGetCommandsCallback& callback,
-    CancelableTaskTracker* tracker) {
-  CancelableTaskTracker::IsCanceledCallback is_canceled;
-  CancelableTaskTracker::TaskId id = tracker->NewTrackedTaskId(&is_canceled);
+    base::CancelableTaskTracker* tracker) {
+  base::CancelableTaskTracker::IsCanceledCallback is_canceled;
+  base::CancelableTaskTracker::TaskId id =
+      tracker->NewTrackedTaskId(&is_canceled);
 
   InternalGetCommandsCallback run_if_not_canceled =
       base::Bind(&RunIfNotCanceled, is_canceled, callback);