Reland of Android: Add support for TraceEvent before the native library is loaded.

chrome/android/java/src/org/chromium/chrome/browser/ChromeApplication.java

 // Copyright 2013 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.chrome.browser;
 
 import android.app.Activity;
 import android.content.Context;
 import android.content.Intent;
 import android.content.SharedPreferences;
@@ skipping 188 matching lines @@
     }
 
     /**
      * This is called once per ChromeApplication instance, which get created per process
      * (browser OR renderer).  Don't stick anything in here that shouldn't be called multiple times
      * during Chrome's lifetime.
      */
     @Override
     public void onCreate() {
         UmaUtils.recordMainEntryPointTime();
+        initCommandLine();
+        TraceEvent.maybeEnableEarlyTracing();
+        TraceEvent.begin("ChromeApplication.onCreate");
+
         super.onCreate();
         ContextUtils.initApplicationContext(this);
 
         UiUtils.setKeyboardShowingDelegate(new UiUtils.KeyboardShowingDelegate() {
             @Override
             public boolean disableKeyboardCheck(Context context, View view) {
                 Activity activity = null;
                 if (context instanceof Activity) {
                     activity = (Activity) context;
                 } else if (view != null && view.getContext() instanceof Activity) {
@@ skipping 18 matching lines @@
 
         // Set minimum Tango log level. This sets an in-memory static field, and needs to be
         // set in the ApplicationContext instead of an activity, since Tango can be woken up
         // by the system directly though messages from GCM.
         AndroidLogger.setMinimumAndroidLogLevel(Log.WARN);
 
         // Set up the identification generator for sync. The ID is actually generated
         // in the SyncController constructor.
         UniqueIdentificationGeneratorFactory.registerGenerator(SyncController.GENERATOR_ID,
                 new UuidBasedUniqueIdentificationGenerator(this, SESSIONS_UUID_PREF_KEY), false);
+        TraceEvent.end("ChromeApplication.onCreate");
     }
 
     /**
      * Each top-level activity (ChromeTabbedActivity, FullscreenActivity) should call this during
      * its onStart phase. When called for the first time, this marks the beginning of a foreground
      * session and calls onForegroundSessionStart(). Subsequent calls are noops until
      * onForegroundSessionEnd() is called, to handle changing top-level Chrome activities in one
      * foreground session.
      */
     public void onStartWithNative() {
@@ skipping 600 matching lines @@
      * Caches flags that are needed by Activities that launch before the native library is loaded
      * and stores them in SharedPreferences. Because this function is called during launch after the
      * library has loaded, they won't affect the next launch until Chrome is restarted.
      */
     private void cacheNativeFlags() {
         if (sIsFinishedCachingNativeFlags) return;
         FeatureUtilities.cacheNativeFlags(this);
         sIsFinishedCachingNativeFlags = true;
     }
 }