Add enable/disable hooks to the InlineUpdateController

Add the ability to turn on/off the InlineUpdateController based on
whether or not there are any active ChromeActivities that are running
(RESUMED).

BUG=922714

Change-Id: I30be4c9894f6be7352f75f2861b6ed5165dd5296
Reviewed-on: https://chromium-review.googlesource.com/c/1468403Reviewed-by: Tommy Nyquist <nyquist@chromium.org>
Cr-Commit-Position: refs/heads/master@{#632329}

chrome/android/java/src/org/chromium/chrome/browser/omaha/UpdateStatusProvider.java

@@ -20,6 +20,9 @@ import android.text.TextUtils;
 
 import com.google.android.gms.common.GooglePlayServicesUtil;
 
+import org.chromium.base.ActivityState;
+import org.chromium.base.ApplicationStatus;
+import org.chromium.base.ApplicationStatus.ActivityStateListener;
 import org.chromium.base.BuildInfo;
 import org.chromium.base.Callback;
 import org.chromium.base.ContextUtils;
@@ -28,6 +31,7 @@ import org.chromium.base.ThreadUtils;
 import org.chromium.base.metrics.RecordHistogram;
 import org.chromium.base.task.AsyncTask;
 import org.chromium.base.task.AsyncTask.Status;
+import org.chromium.chrome.browser.ChromeActivity;
 import org.chromium.chrome.browser.omaha.inline.InlineUpdateController;
 import org.chromium.chrome.browser.preferences.ChromePreferenceManager;
 import org.chromium.chrome.browser.util.ConversionUtils;
@@ -42,7 +46,7 @@ import java.lang.annotation.RetentionPolicy;
  *
  * For manually testing this functionality, see {@link UpdateConfigs}.
  */
-public class UpdateStatusProvider {
+public class UpdateStatusProvider implements ActivityStateListener {
     /** Possible update states. */
     @IntDef({UpdateState.NONE, UpdateState.UPDATE_AVAILABLE, UpdateState.UNSUPPORTED_OS_VERSION,
             UpdateState.INLINE_UPDATE_AVAILABLE, UpdateState.INLINE_UPDATE_DOWNLOADING,
@@ -188,9 +192,28 @@ public class UpdateStatusProvider {
         mInlineController.completeUpdate();
     }
 
+    // ApplicationStateListener implementation.
+    @Override
+    public void onActivityStateChange(Activity changedActivity, @ActivityState int newState) {
+        boolean hasActiveActivity = false;
+
+        for (Activity activity : ApplicationStatus.getRunningActivities()) {
+            if (activity == null || !(activity instanceof ChromeActivity)) continue;
+
+            hasActiveActivity |=
+                    ApplicationStatus.getStateForActivity(activity) == ActivityState.RESUMED;
+            if (hasActiveActivity) break;
+        }
+
+        mInlineController.setEnabled(hasActiveActivity);
+    }
+
     private UpdateStatusProvider() {
         mInlineController = new InlineUpdateController(this::resolveStatus);
         mOmahaQuery = new UpdateQuery(this::resolveStatus);
+
+        // Note that as a singleton this class never unregisters.
+        ApplicationStatus.registerStateListenerForAllActivities(this);
     }
 
     private void pingObservers() {

chrome/android/java/src/org/chromium/chrome/browser/omaha/inline/InlineUpdateController.java

@@ -21,6 +21,9 @@ public class InlineUpdateController {
 
     private final Runnable mCallback;
 
+    private boolean mEnabled;
+    private @Nullable @UpdateState Integer mUpdateState;
+
     /**
      * Builds an instance of {@link InlineUpdateController}.
      * @param callback The {@link Runnable} to notify when an inline update state change occurs.
@@ -28,7 +31,17 @@ public class InlineUpdateController {
     public InlineUpdateController(Runnable callback) {
         mCallback = callback;
 
-        mHandler.post(mCallback);
+        setEnabled(true);
+    }
+
+    public void setEnabled(boolean enabled) {
+        if (mEnabled == enabled) return;
+        mEnabled = enabled;
+
+        if (mEnabled) {
+            mUpdateState = UpdateState.NONE;
+            mHandler.post(mCallback);
+        }
     }
 
     /**
@@ -36,7 +49,7 @@ public class InlineUpdateController {
      * hasn't been determined yet.
      */
     public @Nullable @UpdateState Integer getStatus() {
-        return UpdateState.NONE;
+        return mUpdateState;
     }
 
     /**