LatencyInfo trace_id_ no longer dependent on sequence_number.

ui/latency/ipc/latency_info_param_traits_unittest.cc

 // Copyright 2015 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.
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include "ipc/ipc_message_macros.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "ui/gfx/ipc/geometry/gfx_param_traits.h"
 #include "ui/latency/ipc/latency_info_param_traits.h"
 #include "ui/latency/ipc/latency_info_param_traits_macros.h"
 
 namespace ui {
 
 TEST(LatencyInfoParamTraitsTest, Basic) {
   LatencyInfo latency;
+  latency.set_trace_id(5);
   ASSERT_FALSE(latency.terminated());
   latency.AddLatencyNumber(INPUT_EVENT_LATENCY_ORIGINAL_COMPONENT, 1234, 0);
   latency.AddLatencyNumber(INPUT_EVENT_LATENCY_BEGIN_RWH_COMPONENT, 1234, 100);
   latency.AddLatencyNumber(INPUT_EVENT_LATENCY_TERMINATED_FRAME_SWAP_COMPONENT,
                            1234, 0);
 
-  EXPECT_EQ(100, latency.trace_id());
+  EXPECT_EQ(5, latency.trace_id());
   EXPECT_TRUE(latency.terminated());
 
   IPC::Message msg(1, 2, IPC::Message::PRIORITY_NORMAL);
   IPC::WriteParam(&msg, latency);
   base::PickleIterator iter(msg);
   LatencyInfo output;
   EXPECT_TRUE(IPC::ReadParam(&msg, &iter, &output));
 
   EXPECT_EQ(latency.trace_id(), output.trace_id());
   EXPECT_EQ(latency.terminated(), output.terminated());
@@ skipping 20 matching lines @@
   IPC::WriteParam(&msg, components);
   IPC::WriteParam(&msg, static_cast<int64_t>(1234));
   IPC::WriteParam(&msg, true);
 
   base::PickleIterator iter(msg);
   LatencyInfo output;
   EXPECT_FALSE(IPC::ReadParam(&msg, &iter, &output));
 }
 
 }  // namespace ui