Add new api Activity.getStartInitiatedTime.

This api will return the timestamp at which this activity start was last
initiated by the system. Implementation is wip.

Bug: 9058261
Test: cts-tradefed run singleCommand cts-dev -m CtsAppTestCases -t \
      android.app.cts.ActivityStartTimeTest

Change-Id: I396458ecefbb09108f414b95f9c0beb6d609a4e1
diff --git a/api/current.txt b/api/current.txt
index 41e17b7..a2588f5 100644
--- a/api/current.txt
+++ b/api/current.txt
@@ -3611,6 +3611,7 @@
     method public android.net.Uri getReferrer();
     method public int getRequestedOrientation();
     method public final android.view.SearchEvent getSearchEvent();
+    method public long getStartInitiatedTime();
     method public int getTaskId();
     method public final java.lang.CharSequence getTitle();
     method public final int getTitleColor();
diff --git a/api/system-current.txt b/api/system-current.txt
index 489567e..a6a4ab8 100644
--- a/api/system-current.txt
+++ b/api/system-current.txt
@@ -3737,6 +3737,7 @@
     method public android.net.Uri getReferrer();
     method public int getRequestedOrientation();
     method public final android.view.SearchEvent getSearchEvent();
+    method public long getStartInitiatedTime();
     method public int getTaskId();
     method public final java.lang.CharSequence getTitle();
     method public final int getTitleColor();
diff --git a/api/test-current.txt b/api/test-current.txt
index 27b266d..8659258 100644
--- a/api/test-current.txt
+++ b/api/test-current.txt
@@ -3613,6 +3613,7 @@
     method public android.net.Uri getReferrer();
     method public int getRequestedOrientation();
     method public final android.view.SearchEvent getSearchEvent();
+    method public long getStartInitiatedTime();
     method public int getTaskId();
     method public final java.lang.CharSequence getTitle();
     method public final int getTitleColor();
diff --git a/core/java/android/app/Activity.java b/core/java/android/app/Activity.java
index 06291ab..6019d95 100644
--- a/core/java/android/app/Activity.java
+++ b/core/java/android/app/Activity.java
@@ -18,6 +18,7 @@
 
 import android.metrics.LogMaker;
 import android.graphics.Rect;
+import android.os.SystemClock;
 import android.view.ViewRootImpl.ActivityConfigCallback;
 import android.view.autofill.AutofillId;
 import android.view.autofill.AutofillManager;
@@ -7416,6 +7417,25 @@
         }
     }
 
+    /**
+     * Return the timestamp at which this activity start was last initiated by the system in the
+     * {@link SystemClock#uptimeMillis()} time base.
+     *
+     * This can be used to understand how much time is taken for an activity to be started and
+     * displayed to the user.
+     *
+     * @return timestamp at which this activity start was initiated by the system
+     *         or {@code 0} if for any reason the timestamp could not be retrieved.
+     */
+    public long getStartInitiatedTime() {
+        try {
+            return ActivityManager.getService().getActivityStartInitiatedTime(mToken);
+        } catch (RemoteException e) {
+            Log.e(TAG, "Failed to call getActivityStartTime", e);
+            return 0;
+        }
+    }
+
     class HostCallbacks extends FragmentHostCallback<Activity> {
         public HostCallbacks() {
             super(Activity.this /*activity*/);
diff --git a/core/java/android/app/IActivityManager.aidl b/core/java/android/app/IActivityManager.aidl
index 079bbcd..b98cd85 100644
--- a/core/java/android/app/IActivityManager.aidl
+++ b/core/java/android/app/IActivityManager.aidl
@@ -640,6 +640,8 @@
      */
      void backgroundWhitelistUid(int uid);
 
+     long getActivityStartInitiatedTime(IBinder token);
+
     // WARNING: when these transactions are updated, check if they are any callers on the native
     // side. If so, make sure they are using the correct transaction ids and arguments.
     // If a transaction which will also be used on the native side is being inserted, add it
diff --git a/services/core/java/com/android/server/am/ActivityManagerService.java b/services/core/java/com/android/server/am/ActivityManagerService.java
index 35654d7..05001d5 100644
--- a/services/core/java/com/android/server/am/ActivityManagerService.java
+++ b/services/core/java/com/android/server/am/ActivityManagerService.java
@@ -23809,6 +23809,15 @@
         }
     }
 
+    @Override
+    public long getActivityStartInitiatedTime(IBinder token) {
+        final ActivityRecord r = ActivityRecord.forTokenLocked(token);
+        if (r != null) {
+            return r.mStartInitiatedTimeMs;
+        }
+        return 0;
+    }
+
     void updateApplicationInfoLocked(@NonNull List<String> packagesToUpdate, int userId) {
         final PackageManagerInternal packageManager = getPackageManagerInternalLocked();
         final boolean updateFrameworkRes = packagesToUpdate.contains("android");
diff --git a/services/core/java/com/android/server/am/ActivityRecord.java b/services/core/java/com/android/server/am/ActivityRecord.java
index cfbd2b5..f621bc4 100644
--- a/services/core/java/com/android/server/am/ActivityRecord.java
+++ b/services/core/java/com/android/server/am/ActivityRecord.java
@@ -341,6 +341,12 @@
     private final Rect mBounds = new Rect();
 
     /**
+     * Denotes the timestamp at which this activity start was last initiated in the
+     * {@link SystemClock#uptimeMillis()} time base.
+     */
+    long mStartInitiatedTimeMs;
+
+    /**
      * Temp configs used in {@link #ensureActivityConfigurationLocked(int, boolean)}
      */
     private final Configuration mTmpConfig1 = new Configuration();
@@ -498,6 +504,8 @@
                 pw.print(" forceNewConfig="); pw.println(forceNewConfig);
         pw.print(prefix); pw.print("mActivityType=");
                 pw.println(activityTypeToString(mActivityType));
+        pw.print(prefix); pw.print("mStartInitiatedTimeMs=");
+                TimeUtils.formatDuration(mStartInitiatedTimeMs, now, pw);
         if (requestedVrComponent != null) {
             pw.print(prefix);
             pw.print("requestedVrComponent=");
diff --git a/services/core/java/com/android/server/am/ActivityStarter.java b/services/core/java/com/android/server/am/ActivityStarter.java
index 56594d3..8f1c203 100644
--- a/services/core/java/com/android/server/am/ActivityStarter.java
+++ b/services/core/java/com/android/server/am/ActivityStarter.java
@@ -244,6 +244,7 @@
             ActivityOptions options, boolean ignoreTargetSecurity, boolean componentSpecified,
             ActivityRecord[] outActivity, ActivityStackSupervisor.ActivityContainer container,
             TaskRecord inTask) {
+        final long activityStartTime = SystemClock.uptimeMillis();
         int err = ActivityManager.START_SUCCESS;
 
         ProcessRecord callerApp = null;
@@ -478,6 +479,7 @@
                 callingPackage, intent, resolvedType, aInfo, mService.getGlobalConfiguration(),
                 resultRecord, resultWho, requestCode, componentSpecified, voiceSession != null,
                 mSupervisor, container, options, sourceRecord);
+        r.mStartInitiatedTimeMs = activityStartTime;
         if (outActivity != null) {
             outActivity[0] = r;
         }
@@ -1029,6 +1031,7 @@
                         // so make sure the task now has the identity of the new intent.
                         top.getTask().setIntent(mStartActivity);
                     }
+                    top.mStartInitiatedTimeMs = mStartActivity.mStartInitiatedTimeMs;
                     ActivityStack.logStartActivity(AM_NEW_INTENT, mStartActivity, top.getTask());
                     top.deliverNewIntentLocked(mCallingUid, mStartActivity.intent,
                             mStartActivity.launchedFromPackage);
@@ -1052,6 +1055,7 @@
             setTaskFromIntentActivity(reusedActivity);
 
             if (!mAddingToTask && mReuseTask == null) {
+                reusedActivity.mStartInitiatedTimeMs = mStartActivity.mStartInitiatedTimeMs;
                 // We didn't do anything...  but it was needed (a.k.a., client don't use that
                 // intent!)  And for paranoia, make sure we have correctly resumed the top activity.
                 resumeTargetStackIfNeeded();
@@ -1084,6 +1088,7 @@
                 || mLaunchSingleTop || mLaunchSingleTask);
         if (dontStart) {
             ActivityStack.logStartActivity(AM_NEW_INTENT, top, top.getTask());
+            top.mStartInitiatedTimeMs = mStartActivity.mStartInitiatedTimeMs;
             // For paranoia, make sure we have correctly resumed the top activity.
             topStack.mLastPausedActivity = null;
             if (mDoResume) {
@@ -1664,6 +1669,7 @@
             // desires.
             if (((mLaunchFlags & FLAG_ACTIVITY_SINGLE_TOP) != 0 || mLaunchSingleTop)
                     && intentActivity.realActivity.equals(mStartActivity.realActivity)) {
+                intentActivity.mStartInitiatedTimeMs = mStartActivity.mStartInitiatedTimeMs;
                 ActivityStack.logStartActivity(AM_NEW_INTENT, mStartActivity,
                         intentActivity.getTask());
                 if (intentActivity.frontOfTask) {