Change ThreadChecker example variable name

Don't encourage using |my_thread_checker_| as the name.

Bug: none
Change-Id: I90d7df90131128996e88e2b07f1b3d5f2f51f255
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1758712
Commit-Queue: Wez <wez@chromium.org>
Reviewed-by: Wez <wez@chromium.org>
Cr-Commit-Position: refs/heads/master@{#688169}

base/threading/thread_checker.h

@@ -38,7 +38,7 @@
 //       // It's sometimes useful to detach on construction for objects that are
 //       // constructed in one place and forever after used from another
 //       // thread.
-//       DETACH_FROM_THREAD(my_thread_checker_);
+//       DETACH_FROM_THREAD(thread_checker_);
 //     }
 //
 //     ~MyClass() {
@@ -48,16 +48,16 @@
 //       // knows usage on the associated thread is done. If you're not
 //       // detaching in the constructor, you probably want to explicitly check
 //       // in the destructor.
-//       DCHECK_CALLED_ON_VALID_THREAD(my_thread_checker_);
+//       DCHECK_CALLED_ON_VALID_THREAD(thread_checker_);
 //     }
 //
 //     void MyMethod() {
-//       DCHECK_CALLED_ON_VALID_THREAD(my_thread_checker_);
+//       DCHECK_CALLED_ON_VALID_THREAD(thread_checker_);
 //       ... (do stuff) ...
 //     }
 //
 //    private:
-//     THREAD_CHECKER(my_thread_checker_);
+//     THREAD_CHECKER(thread_checker_);
 //   }
 
 #if DCHECK_IS_ON()

base/threading/thread_checker_unittest.cc

@@ -312,21 +312,21 @@ class ThreadCheckerMacroTest : public testing::Test {
 
   void ExpectDeathOnOtherThread() {
 #if DCHECK_IS_ON()
-    EXPECT_DCHECK_DEATH({ DCHECK_CALLED_ON_VALID_THREAD(my_thread_checker_); });
+    EXPECT_DCHECK_DEATH({ DCHECK_CALLED_ON_VALID_THREAD(thread_checker_); });
 #else
     // Happily no-ops on non-dcheck builds.
-    DCHECK_CALLED_ON_VALID_THREAD(my_thread_checker_);
+    DCHECK_CALLED_ON_VALID_THREAD(thread_checker_);
 #endif
   }
 
   void ExpectNoDeathOnOtherThreadAfterDetach() {
-    DCHECK_CALLED_ON_VALID_THREAD(my_thread_checker_);
-    DCHECK_CALLED_ON_VALID_THREAD(my_thread_checker_)
+    DCHECK_CALLED_ON_VALID_THREAD(thread_checker_);
+    DCHECK_CALLED_ON_VALID_THREAD(thread_checker_)
         << "Make sure it compiles when DCHECK is off";
   }
 
  protected:
-  THREAD_CHECKER(my_thread_checker_);
+  THREAD_CHECKER(thread_checker_);
 
  private:
   DISALLOW_COPY_AND_ASSIGN(ThreadCheckerMacroTest);
@@ -342,7 +342,7 @@ TEST_F(ThreadCheckerMacroTest, Macros) {
   RunCallbackOnNewThreadSynchronously(BindOnce(
       &ThreadCheckerMacroTest::ExpectDeathOnOtherThread, Unretained(this)));
 
-  DETACH_FROM_THREAD(my_thread_checker_);
+  DETACH_FROM_THREAD(thread_checker_);
 
   RunCallbackOnNewThreadSynchronously(
       BindOnce(&ThreadCheckerMacroTest::ExpectNoDeathOnOtherThreadAfterDetach,