Fixing and enhancing OrderedSimpleTaskRunner to allow 100% deterministic tests.

cc/test/begin_frame_args_test.h

 // Copyright 2014 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 CC_TEST_BEGIN_FRAME_ARGS_TEST_H_
 #define CC_TEST_BEGIN_FRAME_ARGS_TEST_H_
 
 #include <iosfwd>
 
 #include "base/time/time.h"
 #include "cc/output/begin_frame_args.h"
+#include "cc/test/ordered_simple_task_runner.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace cc {
 
 // Functions for quickly creating BeginFrameArgs
 BeginFrameArgs CreateBeginFrameArgsForTesting();
 BeginFrameArgs CreateBeginFrameArgsForTesting(int64 frame_time,
                                               int64 deadline,
                                               int64 interval);
 BeginFrameArgs CreateExpiredBeginFrameArgsForTesting();
 
+// Creates a BeginFrameArgs using the fake Now value stored on the
+// OrderSimpleTaskRunner.
+BeginFrameArgs CreateBeginFrameArgsForTesting(
+    const OrderedSimpleTaskRunner& task_runner);

[brianderson, 2014/08/20 20:04:31]

Instead of having such a strong dependency on the OrderedSimpleTask runner, it
would be better to just take in a timestamp for Now.

I don't think OrderedSimpleTaskRunner should be exposing a public version of its
concept of Now() anyway.

[mithro-old, 2014/08/21 17:39:18]

I feel like as the system evolved it might want more information to create the
begin frame args which won't be available just on a timestamp. With the refactor
it's now only dependent on the TestNowSource. It is also a strong signal that
you should be using *this* CreateBeginFrameArgsForTesting (which will get the
right Now() value) rather than the other ones.

+BeginFrameArgs CreateExpiredBeginFrameArgsForTesting(
+    const OrderedSimpleTaskRunner& task_runner);
+
 // gtest helpers -- these *must* be in the same namespace as the types they
 // operate on.
 
 // Allow "EXPECT_EQ(args1, args2);"
 // We don't define operator!= because EXPECT_NE(args1, args2) isn't all that
 // sensible.
 bool operator==(const BeginFrameArgs& lhs, const BeginFrameArgs& rhs);
 
 // Allow gtest to pretty print begin frame args.
 ::std::ostream& operator<<(::std::ostream& os, const BeginFrameArgs& args);
 void PrintTo(const BeginFrameArgs& args, ::std::ostream* os);
 
 }  // namespace cc
 
 #endif  // CC_TEST_BEGIN_FRAME_ARGS_TEST_H_