[CustomTabs] Report the navigation start as absolute time

base/android/time_utils.cc

Index: base/android/time_utils.cc
diff --git a/base/android/time_utils.cc b/base/android/time_utils.cc
new file mode 100644
index 0000000000000000000000000000000000000000..f0e7fd89b567e0d316419d4569e63f3bcab55aac
--- /dev/null
+++ b/base/android/time_utils.cc
@@ -0,0 +1,24 @@
+// 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/time_utils.h"
+
+#include <stdint.h>
+
+#include "base/time/time.h"
+#include "jni/TimeUtils_jni.h"
+
+namespace base {
+namespace android {
+
+static jlong GetTimeTicksNowUs(JNIEnv* env, const JavaParamRef<jclass>& clazz) {
+  return TimeTicks::Now().ToInternalValue();

[Bernhard Bauer, 2016/11/17 16:14:28]

See my comment on
https://codereview.chromium.org/2472163003/diff/100001/chrome/browser/page_lo...:
Can you use `TimeTicks::Now() - TimeTicks()` (and maybe return milliseconds
straight away if that is what Java is also going to use)?

[droger, 2016/11/18 10:23:21]

This is a code move, and this function is already used by other code. So I can't
change the unit.

I can do the difference with TimeTicks() though, it should not break existing
code.

+}
+
+bool RegisterTimeUtils(JNIEnv* env) {
+  return RegisterNativesImpl(env);

[Bryan McQuade, 2016/11/17 13:35:38]

just for my own knowledge, what does this do / why is it needed?

[Bernhard Bauer, 2016/11/17 16:14:28]

This is a generated function in TimeUtils_jni.h that registers the address of
GetTimeTicksNowUs() so it can be called from Java. 

[droger, 2016/11/18 10:23:21]

This is some black magic needed to generate the binding between Java and C++, so
that GetTimeTicksNowUs() can be called from Java.

+}
+
+}  // namespace android
+}  // namespace base