Move platform abstraction to base library

src/sweeper-thread.cc

Index: src/sweeper-thread.cc
diff --git a/src/sweeper-thread.cc b/src/sweeper-thread.cc
index ea2553dfaa4b22189ee3a0f0d3fa59f0c75fc5e3..9ce5ec4d85736657f826b0c42b0f40fad181d6be 100644
--- a/src/sweeper-thread.cc
+++ b/src/sweeper-thread.cc
@@ -67,7 +67,7 @@ void SweeperThread::WaitForSweeperThread() {
 
 
 bool SweeperThread::SweepingCompleted() {
-  bool value = end_sweeping_semaphore_.WaitFor(TimeDelta::FromSeconds(0));
+  bool value = end_sweeping_semaphore_.WaitFor(base::TimeDelta::FromSeconds(0));
   if (value) {
     end_sweeping_semaphore_.Signal();
   }