Introduce ManifestUpgradeDetector for WebAPK to detect web manifest changes.

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

Index: chrome/android/java/src/org/chromium/chrome/browser/webapps/ManifestUpgradeDetector.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/webapps/ManifestUpgradeDetector.java b/chrome/android/java/src/org/chromium/chrome/browser/webapps/ManifestUpgradeDetector.java
new file mode 100644
index 0000000000000000000000000000000000000000..3b3efda710ec17764bc66f490af9e8eed63d49c7
--- /dev/null
+++ b/chrome/android/java/src/org/chromium/chrome/browser/webapps/ManifestUpgradeDetector.java
@@ -0,0 +1,184 @@
+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package org.chromium.chrome.browser.webapps;
+
+import android.content.pm.ApplicationInfo;
+import android.content.pm.PackageManager;
+import android.net.Uri;
+import android.text.TextUtils;
+
+import org.chromium.base.ContextUtils;
+import org.chromium.base.Log;
+import org.chromium.base.VisibleForTesting;
+import org.chromium.base.annotations.CalledByNative;
+import org.chromium.chrome.browser.tab.EmptyTabObserver;
+import org.chromium.chrome.browser.tab.Tab;
+import org.chromium.content_public.browser.WebContents;
+
+/**
+ * This class interacts with C++ to detect whether resources in web manifest of a WebAPK have been
+ * updated.
+ */
+public class ManifestUpgradeDetector extends EmptyTabObserver {
+    /**
+     * The names of <meta-data> in the WebAPK's AndroidManifest.xml whose values are needed to
+     * determine whether a WebAPK needs to be upgraded but which are not present in
+     * {@link WebappInfo}. The names must stay in sync with
+     * {@linkorg.chromium.webapk.lib.runtime_library.HostBrowserLauncher}.
+     */
+    private static final String META_DATA_START_URL = "startUrl";
+
+    /** Pointer to the native side ManifestUpgradeDetector. */
+    private long mNativePointer;
+
+    /** The tab that is being observed. */
+    private final Tab mTab;
+
+    private WebappInfo mWebappInfo;
+
+    private String mStartUrl;
+
+    /**
+     * A flag for whether metadata is set via {@link set*ForTesting()}, rather than set
+     * from WebAPK's AndroidManifest.xml.
+     */
+    private boolean mOverrideMetadataForTesting = false;
+
+    private static final String TAG = "cr_UpgradeDetector";
+
+    public ManifestUpgradeDetector(Tab tab, WebappInfo info) {
+        mTab = tab;
+        mWebappInfo = info;
+    }
+
+    @VisibleForTesting
+    public void setOverrideMetadataForTesting(boolean overrideMetadataForTesting) {
+        mOverrideMetadataForTesting = overrideMetadataForTesting;
+    }
+
+    @VisibleForTesting
+    public void setStartUrlForTesting(String startUrl) {
+        mStartUrl = startUrl;
+    }
+
+    /**
+     * Starts fetching the web manifest resources.
+     */
+    public void start() {
+        if (mWebappInfo.webManifestUri() == null
+                || mWebappInfo.webManifestUri().equals(Uri.EMPTY)) {
+            return;
+        }
+
+        if (mNativePointer != 0) return;
+
+        getMetaDataFromAndroidManifest();
+        mNativePointer = nativeInitialize(mTab.getWebContents(),
+                mWebappInfo.scopeUri().toString(), mWebappInfo.webManifestUri().toString());
+
+        mTab.addObserver(this);
+        nativeStart(mNativePointer);
+    }
+
+    private void getMetaDataFromAndroidManifest() {
+        if (mOverrideMetadataForTesting) {
+            // The metadata are set via {@link set*ForTesting()}.
+            return;
+        }
+        try {
+            ApplicationInfo appinfo =
+                    ContextUtils.getApplicationContext().getPackageManager().getApplicationInfo(
+                            mWebappInfo.webApkPackageName(), PackageManager.GET_META_DATA);
+            mStartUrl = appinfo.metaData.getString(META_DATA_START_URL);
+        } catch (PackageManager.NameNotFoundException e) {
+            e.printStackTrace();
+        }
+    }
+
+    /**
+     * Puts the object in a state where it is safe to be destroyed.
+     */
+    public void destroy() {
+        if (mNativePointer != 0) {
+            nativeDestroy(mNativePointer);
+        }
+        mNativePointer = 0;
+    }
+
+    @Override
+    public void onWebContentsSwapped(Tab tab, boolean didStartLoad,
+            boolean didFinishLoad) {
+        updatePointers();
+    }
+
+    @Override
+    public void onContentChanged(Tab tab) {
+        updatePointers();
+    }
+
+    /**
+     * Updates which WebContents the native ManifestUpgradeDetector is monitoring.
+     */
+    private void updatePointers() {
+        nativeReplaceWebContents(mNativePointer, mTab.getWebContents());
+    }
+
+    /**
+     * Called when the updated Web Manifest has been fetched.
+     */
+    @CalledByNative
+    private void onDataAvailable(String startUrl, String scope, String name, String shortName,
+            int displayMode, int orientation, long themeColor, long backgroundColor) {
+        mTab.removeObserver(this);
+        destroy();
+
+        // TODO(hanxi): crbug.com/627824. Validate whether the new WebappInfo is
+        // WebAPK-compatible.
+        final WebappInfo newInfo = WebappInfo.create(mWebappInfo.id(), startUrl,
+                scope, mWebappInfo.encodedIcon(), name, shortName, displayMode, orientation,
+                mWebappInfo.source(), themeColor, backgroundColor, mWebappInfo.isIconGenerated(),
+                mWebappInfo.webApkPackageName(), mWebappInfo.webManifestUri().toString());
+        if (requireUpgrade(newInfo)) {
+            upgrade();
+        }
+    }
+
+    /**
+     * Checks whether the WebAPK needs to be upgraded provided the new Web Manifest info.
+     */
+    protected boolean requireUpgrade(WebappInfo newInfo) {
+        boolean scopeMatch = mWebappInfo.scopeUri().equals(newInfo.scopeUri());
+        if (!scopeMatch) {
+            // Sometimes the scope doesn't match due to a missing "/" at the end of the scope URL.
+            // Print log to find such cases.
+            Log.d(TAG, "Needs to request update since the scope from WebappInfo (%s) doesn't match"
+                    + "the one fetched from Web Manifest(%s).", mWebappInfo.scopeUri().toString(),
+                    newInfo.scopeUri().toString());
+            return true;
+        }
+
+        // TODO(hanxi): Add icon comparison.
+        if (!TextUtils.equals(mStartUrl, newInfo.uri().toString())
+                || !TextUtils.equals(mWebappInfo.shortName(), newInfo.shortName())
+                || !TextUtils.equals(mWebappInfo.name(), newInfo.name())
+                || mWebappInfo.backgroundColor() != newInfo.backgroundColor()
+                || mWebappInfo.themeColor() != newInfo.themeColor()
+                || mWebappInfo.orientation() != newInfo.orientation()
+                || mWebappInfo.displayMode() != newInfo.displayMode()) {
+            return true;
+        }
+
+        return false;
+    }
+
+    private void upgrade() {}
+
+    private native long nativeInitialize(WebContents webContents, String scope,
+            String webManifestUrl);
+    private native void nativeReplaceWebContents(long nativeManifestUpgradeDetector,
+            WebContents webContents);
+    private native void nativeDestroy(long nativeManifestUpgradeDetector);
+    private native void nativeStart(long nativeManifestUpgradeDetector);
+}