Separate deferred startup into tasks.

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

Index: chrome/android/java/src/org/chromium/chrome/browser/DeferredStartupHandler.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/DeferredStartupHandler.java b/chrome/android/java/src/org/chromium/chrome/browser/DeferredStartupHandler.java
index 1e73dc2ec94a3d73f5509e6e9b3036e0342facf1..d222b8e15a16b14bc88639480c3c1926f7b0ad88 100644
--- a/chrome/android/java/src/org/chromium/chrome/browser/DeferredStartupHandler.java
+++ b/chrome/android/java/src/org/chromium/chrome/browser/DeferredStartupHandler.java
@@ -10,6 +10,8 @@ import android.content.SharedPreferences;
 import android.content.pm.ResolveInfo;
 import android.net.Uri;
 import android.os.AsyncTask;
+import android.os.Looper;
+import android.os.MessageQueue;
 import android.os.SystemClock;
 import android.support.annotation.UiThread;
 import android.support.annotation.WorkerThread;
@@ -45,14 +47,17 @@ import org.chromium.chrome.browser.webapps.WebApkVersionManager;
 import org.chromium.content.browser.ChildProcessLauncher;
 
 import java.util.ArrayList;
+import java.util.LinkedList;
 import java.util.List;
 import java.util.Locale;
+import java.util.Queue;
 import java.util.concurrent.TimeUnit;
 
 /**
  * Handler for application level tasks to be completed on deferred startup.
  */
 public class DeferredStartupHandler {
+    private static final String TAG = "DeferredStartupHandler";
     /** Prevents race conditions when deleting snapshot database. */
     private static final Object SNAPSHOT_DATABASE_LOCK = new Object();
     private static final String SNAPSHOT_DATABASE_REMOVED = "snapshot_database_removed";
@@ -62,8 +67,12 @@ public class DeferredStartupHandler {
         private static final DeferredStartupHandler INSTANCE = new DeferredStartupHandler();
     }
 
-    private boolean mDeferredStartupComplete;
+    private boolean mDeferredStartupInitialized;
+    private boolean mDeferredStartupCompleted;
+    private long mDeferredStartupDuration;
+    private long mMaxTaskDuration;
     private final Context mAppContext;
+    private final Queue<Runnable> mDeferredTasks;
 
     /**
      * This class is an application specific object that handles the deferred startup.
@@ -75,25 +84,147 @@ public class DeferredStartupHandler {
 
     private DeferredStartupHandler() {
         mAppContext = ContextUtils.getApplicationContext();
+        mDeferredTasks = new LinkedList<Runnable>();
+    }
+
+    /**
+     * Initialize and run the next deferred startup task in sequence on the idle handler.
+     */
+    public void runDeferredTasks() {
+        if (!mDeferredStartupInitialized) return;
+
+        // Add UMA task last so we get accurate timing.
+        mDeferredTasks.add(new Runnable() {
+            @Override
+            public void run() {
+                RecordHistogram.recordLongTimesHistogram(
+                        "UMA.Debug.EnableCrashUpload.DeferredStartUpDuration",
+                        mDeferredStartupDuration,
+                        TimeUnit.MILLISECONDS);
+                RecordHistogram.recordLongTimesHistogram(
+                        "UMA.Debug.EnableCrashUpload.DeferredStartUpMaxTaskDuration",
+                        mMaxTaskDuration,
+                        TimeUnit.MILLISECONDS);
+                RecordHistogram.recordLongTimesHistogram(
+                        "UMA.Debug.EnableCrashUpload.DeferredStartUpCompleteTime",
+                        SystemClock.uptimeMillis() - UmaUtils.getForegroundStartTime(),
+                        TimeUnit.MILLISECONDS);
+            }
+        });
+
+        Looper.myQueue().addIdleHandler(new MessageQueue.IdleHandler() {
+            @Override
+            public boolean queueIdle() {
+                Runnable currentTask = mDeferredTasks.poll();
+                if (currentTask == null) {
+                    mDeferredStartupCompleted = true;
+                    return false;
+                }
+
+                long startTime = SystemClock.uptimeMillis();
+                currentTask.run();
+                long timeTaken = SystemClock.uptimeMillis() - startTime;
+
+                mMaxTaskDuration = Math.max(mMaxTaskDuration, timeTaken);
+                mDeferredStartupDuration += timeTaken;
+                return true;
+            }
+        });
+    }
+
+    /**
+     * Adds a single deferred task to the queue.
+     *
+     * @param deferredTask The tasks to be run.
+     */
+    public void addDeferredTask(Runnable deferredTask) {
+        if (mDeferredStartupCompleted) {
+            throw new RuntimeException("Scheduling deferred startup task that will never be run.");
+        }
+        ThreadUtils.assertOnUiThread();
+        mDeferredTasks.add(deferredTask);
     }
 
     /**
      * Handle application level deferred startup tasks that can be lazily done after all
      * the necessary initialization has been completed. Any calls requiring network access should
      * probably go here.
+     *
+     * Keep these tasks short and break up long tasks into multiple smaller tasks, as they run on
+     * the UI thread and are blocking. Remember to follow RAIL guidelines, as much as possible, and
+     * that most devices are quite slow, so leave enough buffer.
      */
     @UiThread
-    public void onDeferredStartupForApp() {
-        if (mDeferredStartupComplete) return;
+    public void initDeferredStartupForApp() {
+        if (mDeferredStartupInitialized) return;
+        mDeferredStartupInitialized = true;
         ThreadUtils.assertOnUiThread();
 
-        long startDeferredStartupTime = SystemClock.uptimeMillis();
-
-        RecordHistogram.recordLongTimesHistogram("UMA.Debug.EnableCrashUpload.DeferredStartUptime",
-                startDeferredStartupTime - UmaUtils.getMainEntryPointTime(),
+        RecordHistogram.recordLongTimesHistogram(
+                "UMA.Debug.EnableCrashUpload.DeferredStartUptime2",
+                SystemClock.uptimeMillis() - UmaUtils.getForegroundStartTime(),
                 TimeUnit.MILLISECONDS);
 
-        // Punt all tasks that may block the UI thread off onto a background thread.
+        mDeferredTasks.add(new Runnable() {
+            @Override
+            public void run() {
+                // Punt all tasks that may block on disk off onto a background thread.
+                initAsyncDiskTask();
+
+                AfterStartupTaskUtils.setStartupComplete();
+
+                PartnerBrowserCustomizations.setOnInitializeAsyncFinished(new Runnable() {
+                    @Override
+                    public void run() {
+                        String homepageUrl = HomepageManager.getHomepageUri(mAppContext);
+                        LaunchMetrics.recordHomePageLaunchMetrics(
+                                HomepageManager.isHomepageEnabled(mAppContext),
+                                NewTabPage.isNTPUrl(homepageUrl), homepageUrl);
+                    }
+                });
+
+                PartnerBookmarksShim.kickOffReading(mAppContext);
+
+                PowerMonitor.create(mAppContext);
+
+                ShareHelper.clearSharedImages(mAppContext);
+            }
+        });
+
+        mDeferredTasks.add(new Runnable() {
+            @Override
+            public void run() {
+                // Clear any media notifications that existed when Chrome was last killed.
+                MediaCaptureNotificationService.clearMediaNotifications(mAppContext);
+
+                startModerateBindingManagementIfNeeded();
+
+                recordKeyboardLocaleUma();
+            }
+        });
+
+        final ChromeApplication application = (ChromeApplication) mAppContext;
+        mDeferredTasks.add(new Runnable() {
+            @Override
+            public void run() {
+                // Start or stop Physical Web
+                PhysicalWeb.onChromeStart(application);
+            }
+        });
+
+        mDeferredTasks.add(new Runnable() {
+            @Override
+            public void run() {
+                // Starts syncing with GSA.
+                application.createGsaHelper().startSync();
+            }
+        });
+
+        // This call will add its own tasks to the queue.
+        application.initializeSharedClasses();
+    }
+
+    private void initAsyncDiskTask() {
         new AsyncTask<Void, Void, Void>() {
             @Override
             protected Void doInBackground(Void... params) {
@@ -104,8 +235,8 @@ public class DeferredStartupHandler {
                             ChromeSwitches.DISABLE_CRASH_DUMP_UPLOAD);
                     if (!crashDumpDisabled) {
                         RecordHistogram.recordLongTimesHistogram(
-                                "UMA.Debug.EnableCrashUpload.Uptime2",
-                                asyncTaskStartTime - UmaUtils.getMainEntryPointTime(),
+                                "UMA.Debug.EnableCrashUpload.Uptime3",
+                                asyncTaskStartTime - UmaUtils.getForegroundStartTime(),
                                 TimeUnit.MILLISECONDS);
                         PrivacyPreferencesManager.getInstance().enablePotentialCrashUploading();
                         MinidumpUploadService.tryUploadAllCrashDumps(mAppContext);
@@ -144,48 +275,6 @@ public class DeferredStartupHandler {
                 }
             }
         }.executeOnExecutor(AsyncTask.THREAD_POOL_EXECUTOR);
-
-        AfterStartupTaskUtils.setStartupComplete();
-
-        PartnerBrowserCustomizations.setOnInitializeAsyncFinished(new Runnable() {
-            @Override
-            public void run() {
-                String homepageUrl = HomepageManager.getHomepageUri(mAppContext);
-                LaunchMetrics.recordHomePageLaunchMetrics(
-                        HomepageManager.isHomepageEnabled(mAppContext),
-                        NewTabPage.isNTPUrl(homepageUrl), homepageUrl);
-            }
-        });
-
-        // TODO(aruslan): http://b/6397072 This will be moved elsewhere
-        PartnerBookmarksShim.kickOffReading(mAppContext);
-
-        PowerMonitor.create(mAppContext);
-
-        ShareHelper.clearSharedImages(mAppContext);
-
-        // Clear any media notifications that existed when Chrome was last killed.
-        MediaCaptureNotificationService.clearMediaNotifications(mAppContext);
-
-        startModerateBindingManagementIfNeeded();
-
-        recordKeyboardLocaleUma();
-
-        ChromeApplication application = (ChromeApplication) mAppContext;
-        // Starts syncing with GSA.
-        application.createGsaHelper().startSync();
-
-        application.initializeSharedClasses();
-
-        // Start or stop Physical Web
-        PhysicalWeb.onChromeStart(application);
-
-        mDeferredStartupComplete = true;
-
-        RecordHistogram.recordLongTimesHistogram(
-                "UMA.Debug.EnableCrashUpload.DeferredStartUpDuration",
-                SystemClock.uptimeMillis() - startDeferredStartupTime,
-                TimeUnit.MILLISECONDS);
     }
 
     private void startModerateBindingManagementIfNeeded() {
@@ -262,6 +351,6 @@ public class DeferredStartupHandler {
     */
     @VisibleForTesting
     public boolean isDeferredStartupComplete() {
-        return mDeferredStartupComplete;
+        return mDeferredStartupCompleted;
     }
 }