[Sync] Refactoring of sync integration test checkers to remove boilerplate await methods.

chrome/browser/sync/test/integration/status_change_checker.cc

Index: chrome/browser/sync/test/integration/status_change_checker.cc
diff --git a/chrome/browser/sync/test/integration/status_change_checker.cc b/chrome/browser/sync/test/integration/status_change_checker.cc
index f5314bbe2133f4eedc198c687e16315e031b07c9..0407390a6a1007322f4b95500922191b0679cbde 100644
--- a/chrome/browser/sync/test/integration/status_change_checker.cc
+++ b/chrome/browser/sync/test/integration/status_change_checker.cc
@@ -9,11 +9,20 @@
 #include "base/run_loop.h"
 #include "base/timer/timer.h"
 
-StatusChangeChecker::StatusChangeChecker() : timed_out_(false) {
-}
+StatusChangeChecker::StatusChangeChecker() : timed_out_(false) {}
 
 StatusChangeChecker::~StatusChangeChecker() {}
 
+bool StatusChangeChecker::Wait() {
+  if (IsExitConditionSatisfied()) {
+    DVLOG(1) << "Already satisfied: " << GetDebugMessage();
+  } else {
+    DVLOG(1) << "Blocking: " << GetDebugMessage();
+    StartBlockingWait();
+  }
+  return !TimedOut();
+}
+
 bool StatusChangeChecker::TimedOut() const {
   return timed_out_;
 }