Mojo: Base our epsilon timeouts off of TestTimeouts::tiny_timeout().

mojo/system/test_utils.h

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef MOJO_SYSTEM_TEST_UTILS_H_
 #define MOJO_SYSTEM_TEST_UTILS_H_
 
 #include <stdint.h>
 
 #include "base/callback_forward.h"
 #include "base/compiler_specific.h"
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
 #include "base/task_runner.h"
 #include "base/threading/thread.h"
 #include "base/time/time.h"
 
 namespace tracked_objects {
 class Location;
 }
 
 namespace mojo {
 namespace system {
 namespace test {
 
+// Posts the given task (to the given task runner) and waits for it to complete.
+// (Note: Doesn't spin the current thread's message loop, so if you're careless
+// this could easily deadlock.)
+void PostTaskAndWait(scoped_refptr<base::TaskRunner> task_runner,
+                     const tracked_objects::Location& from_here,
+                     const base::Closure& task);
+
+// A timeout smaller than |TestTimeouts::tiny_timeout()|. Warning: This may lead
+// to flakiness, but this is unavoidable if, e.g., you're trying to ensure that
+// functions with timeouts are reasonably accurate. We want this to be as small
+// as possible without causing too much flakiness.
+base::TimeDelta EpsilonTimeout();
+
+// Stopwatch -------------------------------------------------------------------
+
+// A simple "stopwatch" for measuring time elapsed from a given starting point.
 class Stopwatch {
  public:
   Stopwatch() {}
   ~Stopwatch() {}
 
   void Start() {
     start_time_ = base::TimeTicks::HighResNow();
   }
 
-  int64_t Elapsed() {
-    return (base::TimeTicks::HighResNow() - start_time_).InMicroseconds();
+  base::TimeDelta Elapsed() {
+    return base::TimeTicks::HighResNow() - start_time_;
   }
 
  private:
   base::TimeTicks start_time_;
 
   DISALLOW_COPY_AND_ASSIGN(Stopwatch);
 };
 
-// Posts the given task (to the given task runner) and waits for it to complete.
-// (Note: Doesn't spin the current thread's message loop, so if you're careless
-// this could easily deadlock.)
-void PostTaskAndWait(scoped_refptr<base::TaskRunner> task_runner,
-                     const tracked_objects::Location& from_here,
-                     const base::Closure& task);
-
 // TestIOThread ----------------------------------------------------------------
 
 class TestIOThread {
  public:
   enum Mode { kAutoStart, kManualStart };
   explicit TestIOThread(Mode mode);
   // Stops the I/O thread if necessary.
   ~TestIOThread();
 
   // |Start()|/|Stop()| should only be called from the main (creation) thread.
@@ skipping 20 matching lines @@
   bool io_thread_started_;
 
   DISALLOW_COPY_AND_ASSIGN(TestIOThread);
 };
 
 }  // namespace test
 }  // namespace system
 }  // namespace mojo
 
 #endif  // MOJO_SYSTEM_TEST_UTILS_H_