android: Add thread time to early TraceEvent, make timings more precise.

base/android/java/src/org/chromium/base/EarlyTraceEvent.java

 // 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.
 
 package org.chromium.base;
 
+import android.annotation.SuppressLint;
+import android.os.Build;
 import android.os.Process;
 import android.os.StrictMode;
 import android.os.SystemClock;
 
 import org.chromium.base.annotations.JNINamespace;
 import org.chromium.base.annotations.MainDex;
 import org.chromium.base.annotations.SuppressFBWarnings;
 
 import java.io.File;
 import java.util.ArrayList;
@@ skipping 21 matching lines @@
 @MainDex
 public class EarlyTraceEvent {
     // Must be kept in sync with the native kAndroidTraceConfigFile.
     private static final String TRACE_CONFIG_FILENAME = "/data/local/chrome-trace-config.json";
 
     /** Single trace event. */
     @VisibleForTesting
     static final class Event {
         final String mName;
         final int mThreadId;
-        final long mBeginTimeMs;
-        long mEndTimeMs;
+        final long mBeginTimeNanos;
+        final long mBeginThreadTimeMillis;
+        long mEndTimeNanos;
+        long mEndThreadTimeMillis;
 
         Event(String name) {
             mName = name;
             mThreadId = Process.myTid();
-            mBeginTimeMs = SystemClock.elapsedRealtime();
+            mBeginTimeNanos = elapsedRealtimeNanos();
+            mBeginThreadTimeMillis = SystemClock.currentThreadTimeMillis();
         }
 
         void end() {
-            assert mEndTimeMs == 0;
-            mEndTimeMs = SystemClock.elapsedRealtime();
+            assert mEndTimeNanos == 0;
+            assert mEndThreadTimeMillis == 0;
+            mEndTimeNanos = elapsedRealtimeNanos();
+            mEndThreadTimeMillis = SystemClock.currentThreadTimeMillis();
+        }
+
+        @SuppressLint("NewApi")
+        private static long elapsedRealtimeNanos() {
+            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN_MR1) {
+                return SystemClock.elapsedRealtimeNanos();
+            } else {
+                return SystemClock.elapsedRealtime() * 1000000;
+            }
         }
     }
 
     // State transitions are:
     // - enable(): DISABLED -> ENABLED
     // - disable(): ENABLED -> FINISHING
     // - Once there are no pending events: FINISHING -> FINISHED.
     @VisibleForTesting static final int STATE_DISABLED = 0;
     @VisibleForTesting static final int STATE_ENABLED = 1;
     @VisibleForTesting static final int STATE_FINISHING = 2;
@@ skipping 99 matching lines @@
 
     private static void maybeFinishLocked() {
         if (!sPendingEvents.isEmpty()) return;
         sState = STATE_FINISHED;
         dumpEvents(sCompletedEvents);
         sCompletedEvents = null;
         sPendingEvents = null;
     }
 
     private static void dumpEvents(List<Event> events) {
-        long nativeNowUs = TimeUtils.nativeGetTimeTicksNowUs();
-        long javaNowUs = SystemClock.elapsedRealtime() * 1000;
-        long offsetMs = (nativeNowUs - javaNowUs) / 1000;
-        for (Event event : events) {
-            nativeRecordEarlyEvent(event.mName, event.mBeginTimeMs + offsetMs,
-                    event.mEndTimeMs + offsetMs, event.mThreadId);
+        long nativeNowNanos = TimeUtils.nativeGetTimeTicksNowUs() * 1000;
+        long javaNowNanos = Event.elapsedRealtimeNanos();
+        long offsetNanos = nativeNowNanos - javaNowNanos;
+        for (Event e : events) {
+            nativeRecordEarlyEvent(e.mName, e.mBeginTimeNanos + offsetNanos,
+                    e.mEndTimeNanos + offsetNanos, e.mThreadId,
+                    e.mEndThreadTimeMillis - e.mBeginThreadTimeMillis);
         }
     }
 
-    private static native void nativeRecordEarlyEvent(
-            String name, long beginTimeMs, long endTimeMs, int threadId);
+    private static native void nativeRecordEarlyEvent(String name, long beginTimNanos,
+            long endTimeNanos, int threadId, long threadDurationMillis);
 }