[CustomTabs] Report the navigation start as absolute time

base/android/early_trace_event_binding.cc

 // Copyright 2016 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 "base/android/early_trace_event_binding.h"
 
 #include <stdint.h>
 
 #include "base/android/jni_string.h"
 #include "base/time/time.h"
 #include "base/trace_event/trace_event.h"
 #include "jni/EarlyTraceEvent_jni.h"
 
 namespace base {
 namespace android {
 
 const char kEarlyJavaCategory[] = "EarlyJava";
 
-static jlong GetTimeTicksNowUs(JNIEnv* env, const JavaParamRef<jclass>& clazz) {
-  return TimeTicks::Now().ToInternalValue();
-}
-
 static void RecordEarlyEvent(JNIEnv* env,
                              const JavaParamRef<jclass>& clazz,
                              const JavaParamRef<jstring>& jname,
                              jlong begin_time_ms,
                              jlong end_time_ms,
                              jint thread_id) {
   std::string name = ConvertJavaStringToUTF8(env, jname);
   int64_t begin_us = begin_time_ms * 1000;
   int64_t end_us = end_time_ms * 1000;
 
   INTERNAL_TRACE_EVENT_ADD_WITH_ID_TID_AND_TIMESTAMP(
       TRACE_EVENT_PHASE_BEGIN, kEarlyJavaCategory, name.c_str(),
       trace_event_internal::kNoId, thread_id,
       TimeTicks::FromInternalValue(begin_us), TRACE_EVENT_FLAG_COPY);
   INTERNAL_TRACE_EVENT_ADD_WITH_ID_TID_AND_TIMESTAMP(
       TRACE_EVENT_PHASE_END, kEarlyJavaCategory, name.c_str(),
       trace_event_internal::kNoId, thread_id,
       TimeTicks::FromInternalValue(end_us), TRACE_EVENT_FLAG_COPY);
 }
 
 bool RegisterEarlyTraceEvent(JNIEnv* env) {
   return RegisterNativesImpl(env);
 }
 
 }  // namespace android
 }  // namespace base