Use mojo for WebappRegistry.

chrome/android/java/src/org/chromium/chrome/browser/mojo/ChromeInterfaceRegistrar.java

Index: chrome/android/java/src/org/chromium/chrome/browser/mojo/ChromeInterfaceRegistrar.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/mojo/ChromeInterfaceRegistrar.java b/chrome/android/java/src/org/chromium/chrome/browser/mojo/ChromeInterfaceRegistrar.java
index 7dd8ff7e0eedd57229ce964caca6a30e3505c735..dbb39a8261113071f728432d55e07f89ffe05005 100644
--- a/chrome/android/java/src/org/chromium/chrome/browser/mojo/ChromeInterfaceRegistrar.java
+++ b/chrome/android/java/src/org/chromium/chrome/browser/mojo/ChromeInterfaceRegistrar.java
@@ -8,6 +8,7 @@ import android.content.Context;
 
 import org.chromium.base.annotations.CalledByNative;
 import org.chromium.chrome.browser.payments.PaymentRequestFactory;
+import org.chromium.chrome.browser.webapps.WebappRegistry;
 import org.chromium.chrome.browser.webshare.ShareServiceImplementationFactory;
 import org.chromium.content_public.browser.InterfaceRegistrar;
 import org.chromium.content_public.browser.WebContents;
@@ -37,5 +38,9 @@ class ChromeWebContentsInterfaceRegistrar implements InterfaceRegistrar<WebConte
 }
 class ChromeContextInterfaceRegistrar implements InterfaceRegistrar<Context> {
     @Override
-    public void registerInterfaces(InterfaceRegistry registry, final Context applicationContext) {}
+    public void registerInterfaces(InterfaceRegistry registry, final Context applicationContext) {
+        registry.addInterface(new InterfaceBinderImpl<org.chromium.mojom.chrome.WebappRegistry>(
+                org.chromium.mojom.chrome.WebappRegistry.MANAGER,
+                new WebappRegistry.Factory(applicationContext)));
+    }
 }