Separate deferred startup into tasks.

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 246 matching lines @@
      * 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() {
         if (mIsStarted) return;
         mIsStarted = true;
 
         assert mIsProcessInitialized;
 
+        UmaUtils.recordForegroundStartTime();

[Yusuf, 2016/07/12 18:00:19]

I would say this is a bit misleading. The previous value you are getting rid of
is called from onCreate in application. We rename it here to be related with
foreground and then call it in startwithnative which is called after all the
native libraries have been loaded and onCreateWithNative in
ChromeBrowserInitializer is completed. That means we have run through all UI
initialization (with and without native) and completed all those tasks, by the
time we are here. I agree that we are probably in the foreground by now, but we
can't know how much time has passed since being in foreground (We have other
stats around for first draw etc). Android makes the first draw after the first
onResume call which may have happened way before this is called.

I guess my question is what we are measuring here, is it going to be only
related with deferred startup or will this starting time effect other
historgrams related with startup as well? If latter, then we may want to rething
where we are putting this.

[Peter Wen, 2016/07/12 19:02:13]

This is currently used only by deferred startup and
Startup.FirstCommitNavigationTime, which is owned by pasko@. Thus risk to
startup metrics is low.

The other reason to move this here is to have a more reliable baseline, as the
previous time recorded in onCreate was very misleading due to it being recorded
on app installation rather than app startup. Is there a better place for this
concept?

         onForegroundSessionStart();
         cacheNativeFlags();
     }
 
     /**
      * Called when a top-level Chrome activity (ChromeTabbedActivity, FullscreenActivity) is
      * started in foreground. It will not be called again when other Chrome activities take over
      * (see onStart()), that is, when correct activity calls startActivity() for another Chrome
      * activity.
      */
@@ skipping 163 matching lines @@
     }
 
     /**
      * The host activity should call this after the native library has loaded to ensure classes
      * shared by Activities in the same process are properly initialized.
      */
     public void initializeSharedClasses() {
         if (mInitializedSharedClasses) return;
         mInitializedSharedClasses = true;
 
-        ForcedSigninProcessor.start(this);
-        AccountsChangedReceiver.addObserver(new AccountsChangedReceiver.AccountsChangedObserver() {
+        DeferredStartupHandler.getInstance().addDeferredTask(new Runnable() {
             @Override
-            public void onAccountsChanged(Context context, Intent intent) {
-                ThreadUtils.runOnUiThread(new Runnable() {
-                    @Override
-                    public void run() {
-                        ForcedSigninProcessor.start(ChromeApplication.this);
-                    }
-                });
+            public void run() {
+                ForcedSigninProcessor.start(getApplicationContext());
+                AccountsChangedReceiver.addObserver(
+                        new AccountsChangedReceiver.AccountsChangedObserver() {
+                            @Override
+                            public void onAccountsChanged(Context context, Intent intent) {
+                                ThreadUtils.runOnUiThread(new Runnable() {
+                                    @Override
+                                    public void run() {
+                                        ForcedSigninProcessor.start(getApplicationContext());
+                                    }
+                                });
+                            }
+                        });
             }
         });
-        GoogleServicesManager.get(this).onMainActivityStart();
-        RevenueStats.getInstance();
 
-        mDevToolsServer = new DevToolsServer(DEV_TOOLS_SERVER_SOCKET_PREFIX);
-        mDevToolsServer.setRemoteDebuggingEnabled(
-                true, DevToolsServer.Security.ALLOW_DEBUG_PERMISSION);
+        DeferredStartupHandler.getInstance().addDeferredTask(new Runnable() {
+            @Override
+            public void run() {
+                GoogleServicesManager.get(getApplicationContext())

[Yusuf, 2016/07/12 18:00:19]

this can fit in one line?

[Peter Wen, 2016/07/12 19:02:13]

Done.

+                        .onMainActivityStart();
+                RevenueStats.getInstance();
+            }
+        });
 
-        startApplicationActivityTracker();
+        DeferredStartupHandler.getInstance().addDeferredTask(new Runnable() {
+            @Override
+            public void run() {
+                mDevToolsServer = new DevToolsServer(DEV_TOOLS_SERVER_SOCKET_PREFIX);
+                mDevToolsServer.setRemoteDebuggingEnabled(
+                        true, DevToolsServer.Security.ALLOW_DEBUG_PERMISSION);
 
-        // Add process check to diagnose http://crbug.com/606309. Remove this after the bug is
-        // fixed.
-        assert !CommandLine.getInstance().hasSwitch(ContentSwitches.SWITCH_PROCESS_TYPE);
-        if (!CommandLine.getInstance().hasSwitch(ContentSwitches.SWITCH_PROCESS_TYPE)) {
-            DownloadController.setDownloadNotificationService(
-                    DownloadManagerService.getDownloadManagerService(this));
-        }
+                startApplicationActivityTracker();
+            }
+        });
 
-        if (ApiCompatibilityUtils.isPrintingSupported()) {
-            mPrintingController = PrintingControllerFactory.create(getApplicationContext());
-        }
+        DeferredStartupHandler.getInstance().addDeferredTask(new Runnable() {
+            @Override
+            public void run() {
+                // Add process check to diagnose http://crbug.com/606309. Remove this after the bug
+                // is fixed.
+                assert !CommandLine.getInstance().hasSwitch(ContentSwitches.SWITCH_PROCESS_TYPE);
+                if (!CommandLine.getInstance().hasSwitch(ContentSwitches.SWITCH_PROCESS_TYPE)) {
+                    DownloadController.setDownloadNotificationService(
+                            DownloadManagerService.getDownloadManagerService(
+                                    getApplicationContext()));
+                }
+
+                if (ApiCompatibilityUtils.isPrintingSupported()) {
+                    mPrintingController = PrintingControllerFactory.create(getApplicationContext());
+                }
+            }
+        });
     }
 
     /**
      * For extending classes to carry out tasks that initialize the browser process.
      * Should be called almost immediately after the native library has loaded to initialize things
      * that really, really have to be set up early.  Avoid putting any long tasks here.
      */
     public void initializeProcess() {
         if (mIsProcessInitialized) return;
         mIsProcessInitialized = true;
@@ skipping 370 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;
     }
 }