Make RemoteObjectHostImpl#close properly close the registry.

Noticed by inspection of the code which was obviously wrong.
Added a test for this.

Bug: 794320
Change-Id: Idca62abb1e9ec8719235528b213f9ca5f7e82e0a
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1829760
Auto-Submit: Jeremy Roman <jbroman@chromium.org>
Commit-Queue: Bo <boliu@chromium.org>
Reviewed-by: Bo <boliu@chromium.org>
Cr-Commit-Position: refs/heads/master@{#700878}

content/public/android/java/src/org/chromium/content/browser/remoteobjects/RemoteObjectHostImpl.java

@@ -83,7 +83,7 @@ class RemoteObjectHostImpl implements RemoteObjectHost {
     @Override
     public void close() {
         RemoteObjectRegistry registry = mRegistry.get();
-        if (registry != null) {
+        if (registry == null) {
             return;
         }
         registry.close();

content/public/android/javatests/src/org/chromium/content/browser/remoteobjects/RemoteObjectHostImplTest.java

@@ -4,6 +4,9 @@
 
 package org.chromium.content.browser.remoteobjects;
 
+import static org.hamcrest.Matchers.isIn;
+import static org.hamcrest.Matchers.not;
+
 import android.support.test.filters.SmallTest;
 
 import org.junit.Assert;
@@ -146,4 +149,15 @@ public final class RemoteObjectHostImplTest {
         host.releaseObject(id);
         Assert.assertNull(mRegistry.getObjectById(id));
     }
+
+    @Test
+    @SmallTest
+    @Feature({"AndroidWebView", "Android-JavaBridge"})
+    public void testClose() {
+        RemoteObjectHostImpl host = new RemoteObjectHostImpl(
+                TestJavascriptInterface.class, /* auditor */ null, mRegistry);
+        Assert.assertThat(mRegistry, isIn(mRetainingSet));
+        host.close();
+        Assert.assertThat(mRegistry, not(isIn(mRetainingSet)));
+    }
 }