Add Digital Asset Links verification for postMessage API

chrome/android/java/src/org/chromium/chrome/browser/customtabs/PostMessageHandler.java

Index: chrome/android/java/src/org/chromium/chrome/browser/customtabs/PostMessageHandler.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/customtabs/PostMessageHandler.java b/chrome/android/java/src/org/chromium/chrome/browser/customtabs/PostMessageHandler.java
index f49c1957d3d354510e502a3fa2231237cb0c8bca..4ac2c95eb2114b09948930f5bb72fe49347847e8 100644
--- a/chrome/android/java/src/org/chromium/chrome/browser/customtabs/PostMessageHandler.java
+++ b/chrome/android/java/src/org/chromium/chrome/browser/customtabs/PostMessageHandler.java
@@ -6,12 +6,15 @@ package org.chromium.chrome.browser.customtabs;
 
 import android.content.Context;
 import android.net.Uri;
+import android.support.annotation.NonNull;
 import android.support.customtabs.CustomTabsService;
 import android.support.customtabs.CustomTabsSessionToken;
 import android.support.customtabs.PostMessageServiceConnection;
 
 import org.chromium.base.ContextUtils;
 import org.chromium.base.ThreadUtils;
+import org.chromium.base.VisibleForTesting;
+import org.chromium.chrome.browser.customtabs.OriginVerifier.OriginVerificationListener;
 import org.chromium.chrome.browser.tab.Tab;
 import org.chromium.content.browser.AppWebMessagePort;
 import org.chromium.content_public.browser.MessagePort;
@@ -22,13 +25,16 @@ import org.chromium.content_public.browser.WebContentsObserver;
 /**
  * A class that handles postMessage communications with a designated {@link CustomTabsSessionToken}.
  */
-public class PostMessageHandler extends PostMessageServiceConnection {
+public class PostMessageHandler
+        extends PostMessageServiceConnection implements OriginVerificationListener {
     private final MessageCallback mMessageCallback;
+    private OriginVerifier mOriginVerifier;
     private WebContents mWebContents;
     private boolean mMessageChannelCreated;
     private boolean mBoundToService;
     private AppWebMessagePort[] mChannel;
     private Uri mOrigin;
+    private String mPackageName;
 
     /**
      * Basic constructor. Everytime the given {@link CustomTabsSessionToken} is associated with a
@@ -49,6 +55,14 @@ public class PostMessageHandler extends PostMessageServiceConnection {
     }
 
     /**
+     * Sets the package name unique to the session.
+     * @param packageName The package name for the client app for the owning session.
+     */
+    void setPackageName(@NonNull String packageName) {
+        mPackageName = packageName;
+    }
+
+    /**
      * Resets the internal state of the handler, linking the associated
      * {@link CustomTabsSessionToken} with a new {@link WebContents} and the {@link Tab} that
      * contains it.
@@ -127,6 +141,22 @@ public class PostMessageHandler extends PostMessageServiceConnection {
     }
 
     /**
+     * Asynchronously verify the postMessage origin for the given package name and initialize with
+     * it if the result is a success. Can be called multiple times. If so, the previous requests
+     * will be overridden.
+     * @param origin The origin to verify for.
+     */
+    public void verifyAndInitializeWithOrigin(final Uri origin) {
+        if (mOriginVerifier == null) mOriginVerifier = new OriginVerifier(this, mPackageName);
+        ThreadUtils.postOnUiThread(new Runnable() {
+            @Override
+            public void run() {
+                mOriginVerifier.start(origin);
+            }
+        });
+    }
+
+    /**
      * Relay a postMessage request through the current channel assigned to this session.
      * @param message The message to be sent.
      * @return The result of the postMessage request. Returning true means the request was accepted,
@@ -166,4 +196,27 @@ public class PostMessageHandler extends PostMessageServiceConnection {
     public void onPostMessageServiceDisconnected() {
         mBoundToService = false;
     }
+
+    @Override
+    public void onOriginVerified(String packageName, Uri origin, boolean result) {
+        if (!result) return;
+        initializeWithOrigin(origin);
+    }
+
+    /**
+     * @return The origin that has been declared for this handler.
+     */
+    @VisibleForTesting
+    Uri getOriginForTesting() {
+        return mOrigin;
+    }
+
+    /**
+     * Cleans up any dependencies that this handler might have.
+     * @param context Context to use for unbinding if necessary.
+     */
+    void cleanup(Context context) {
+        if (mBoundToService) super.unbindFromContext(context);
+        if (mOriginVerifier != null) mOriginVerifier.cleanUp();
+    }
 }