Introduce ManifestUpgradeDetector for WebAPK to detect web manifest changes.

chrome/android/java/src/org/chromium/chrome/browser/webapps/WebApkActivity.java

Index: chrome/android/java/src/org/chromium/chrome/browser/webapps/WebApkActivity.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/webapps/WebApkActivity.java b/chrome/android/java/src/org/chromium/chrome/browser/webapps/WebApkActivity.java
index 28547bfbc1c1751139565e3e3d2f1112552c8a49..8800eaac3d4afe6e27bf4c83f7204b49c8c9f987 100644
--- a/chrome/android/java/src/org/chromium/chrome/browser/webapps/WebApkActivity.java
+++ b/chrome/android/java/src/org/chromium/chrome/browser/webapps/WebApkActivity.java
@@ -28,6 +28,10 @@ import org.chromium.webapk.lib.client.WebApkServiceConnectionManager;
  * UI-less Chrome.
  */
 public class WebApkActivity extends WebappActivity {
+    private static final String TAG = "cr_WebApkActivity";
+    private ManifestUpgradeDetector mManifestUpgradeDetector = null;
+    private boolean mIsWebApkRegistered = false;
+
     @Override
     protected void onNewIntent(Intent intent) {
         super.onNewIntent(intent);
@@ -59,12 +63,13 @@ public class WebApkActivity extends WebappActivity {
                         @Override
                         public void onWebappDataStorageRetrieved(
                                 WebappDataStorage storage) {
-                            storage.updateFromShortcutIntent(getIntent());
+                            storage.updateFromShortcutIntent(getIntent(), true);
+                            mIsWebApkRegistered = true;
                         }
                     });
             return;
         }
-
+        mIsWebApkRegistered = true;
         // Update WebappInfo from WebappDataStorage because the information in WebappDataStorage
         // is more up to date than the information in the launch intent. Whenever the Web Manifest
         // changes, WebappDataStorage is updated. Depending on which of the Web Manifest's fields
@@ -144,6 +149,16 @@ public class WebApkActivity extends WebappActivity {
     }
 
     @Override
+    protected void checkUpdates() {
+        // TODO(hanxi): Asks WebApk's update manager whether to check resources updates.
+        if (mManifestUpgradeDetector == null && mIsWebApkRegistered) {
+            mManifestUpgradeDetector =
+                    new ManifestUpgradeDetector(this, getActivityTab(), mWebappInfo);
+        }
+        mManifestUpgradeDetector.start();
+    }
+
+    @Override
     public void onPause() {
         super.onPause();
         initializeChildProcessCreationParams(false);
@@ -165,4 +180,12 @@ public class WebApkActivity extends WebappActivity {
         }
         ChildProcessCreationParams.set(params);
     }
+
+    @Override
+    protected void onDestroyInternal() {
+        if (mManifestUpgradeDetector != null) {
+            mManifestUpgradeDetector.destroy();
+        }
+        super.onDestroyInternal();
+    }
 }