Preserve failure history when calling startObservingHealth

Instead of always creating a new MonitoredPackage every time
PackageWatchdog#startObservingHealth is called, just update
the duration of an existing MonitoredPackage if one exists. This
means that the failure history will be preserved.

Test: atest PackageWatchdogTest
Bug: 150114865
Change-Id: I6d6e3e0e893a603fda50df833bc5b6ce1757b6ec

services/core/java/com/android/server/PackageWatchdog.java

@@ -1062,7 +1062,12 @@ public class PackageWatchdog {
         public void updatePackagesLocked(List<MonitoredPackage> packages) {
             for (int pIndex = 0; pIndex < packages.size(); pIndex++) {
                 MonitoredPackage p = packages.get(pIndex);
-                this.packages.put(p.getName(), p);
+                MonitoredPackage existingPackage = this.packages.get(p.getName());
+                if (existingPackage != null) {
+                    existingPackage.updateHealthCheckDuration(p.mDurationMs);
+                } else {
+                    this.packages.put(p.getName(), p);
+                }
             }
         }
 
@@ -1331,6 +1336,12 @@ public class PackageWatchdog {
             return updateHealthCheckStateLocked();
         }
 
+        /** Explicitly update the monitoring duration of the package. */
+        @GuardedBy("mLock")
+        public void updateHealthCheckDuration(long newDurationMs) {
+            mDurationMs = newDurationMs;
+        }
+
         /**
          * Marks the health check as passed and transitions to {@link HealthCheckState.PASSED}
          * if not yet {@link HealthCheckState.FAILED}.

tests/PackageWatchdog/src/com/android/server/PackageWatchdogTest.java

@@ -1123,6 +1123,28 @@ public class PackageWatchdogTest {
         assertThat(testController.getSyncRequests()).isEqualTo(expectedSyncRequests);
     }
 
+    /**
+     * Ensure that the failure history of a package is preserved when making duplicate calls to
+     * observe the package.
+     */
+    @Test
+    public void testFailureHistoryIsPreserved() {
+        PackageWatchdog watchdog = createWatchdog();
+        TestObserver observer = new TestObserver(OBSERVER_NAME_1);
+        watchdog.startObservingHealth(observer, List.of(APP_A), SHORT_DURATION);
+        for (int i = 0; i < PackageWatchdog.DEFAULT_TRIGGER_FAILURE_COUNT - 1; i++) {
+            watchdog.onPackageFailure(List.of(new VersionedPackage(APP_A, VERSION_CODE)),
+                    PackageWatchdog.FAILURE_REASON_UNKNOWN);
+        }
+        mTestLooper.dispatchAll();
+        assertThat(observer.mMitigatedPackages).isEmpty();
+        watchdog.startObservingHealth(observer, List.of(APP_A), LONG_DURATION);
+        watchdog.onPackageFailure(List.of(new VersionedPackage(APP_A, VERSION_CODE)),
+                PackageWatchdog.FAILURE_REASON_UNKNOWN);
+        mTestLooper.dispatchAll();
+        assertThat(observer.mMitigatedPackages).isEqualTo(List.of(APP_A));
+    }
+
     private void adoptShellPermissions(String... permissions) {
         InstrumentationRegistry
                 .getInstrumentation()