Use macros for SequenceChecker docs.

Macros are preferred to direct access to class methods, as they are less
expensive in production code.

BUG=689520
TEST=none
[email protected]

Review-Url: https://codereview.chromium.org/2956033003
Cr-Commit-Position: refs/heads/master@{#482707}
diff --git a/docs/threading_and_tasks.md b/docs/threading_and_tasks.md
index 6cc56bdc..280f1f25 100644
--- a/docs/threading_and_tasks.md
+++ b/docs/threading_and_tasks.md
@@ -189,17 +189,17 @@
  public:
   A() {
     // Do not require accesses to be on the creation sequence.
-    sequence_checker_.DetachFromSequence();
+    DETACH_FROM_SEQUENCE(sequence_checker_);
   }
 
   void AddValue(int v) {
     // Check that all accesses are on the same sequence.
-    DCHECK(sequence_checker_.CalledOnValidSequence());
+    DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
     values_.push_back(v);
 }
 
  private:
-  base::SequenceChecker sequence_checker_;
+  SEQUENCE_CHECKER(sequence_checker_);
 
   // No lock required, because all accesses are on the
   // same sequence.