customtabs: Don't crash when the death notificaton is sent to a random thread.

chrome/android/javatests/src/org/chromium/chrome/browser/customtabs/CustomTabsConnectionTest.java

 // Copyright 2015 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.customtabs;
 
 import static org.chromium.base.test.util.Restriction.RESTRICTION_TYPE_NON_LOW_END_DEVICE;
 
 import android.app.Application;
 import android.content.Context;
@@ skipping 128 matching lines @@
                 String referrer =
                         mCustomTabsConnection.getReferrerForSession(token).getUrl();
                 WebContents webContents =
                         mCustomTabsConnection.takePrerenderedUrl(token, URL, referrer);
                 assertNotNull(webContents);
                 webContents.destroy();
             }
         });
     }
 
+    /*
+     * Tests that when the disconnection notification comes from a non-UI thread, Chrome doesn't
+     * crash. Non-regression test for crbug.com/623128.
+     */
+    @SmallTest
+    @Restriction(RESTRICTION_TYPE_NON_LOW_END_DEVICE)
+    public void testPrerenderAndDisconnectOnOtherThread() {
+        final CustomTabsSessionToken token = assertWarmupAndMayLaunchUrl(null, URL, true);
+        final Thread otherThread = new Thread(new Runnable() {
+            @Override
+            public void run() {
+                mCustomTabsConnection.cleanUpSession(token);
+            }
+        });
+
+        ThreadUtils.runOnUiThreadBlocking(new Runnable() {
+            @Override
+            public void run() {
+                otherThread.start();
+            }
+        });
+        // Should not crash, hence no assertions below.
+    }
+
     @SmallTest
     @Restriction(RESTRICTION_TYPE_NON_LOW_END_DEVICE)
     public void testMayLaunchUrlKeepsSpareRendererWithoutPrerendering() {
         assertTrue(mCustomTabsConnection.warmup(0));
         final CustomTabsSessionToken token =
                 CustomTabsSessionToken.createDummySessionTokenForTesting();
         assertTrue(mCustomTabsConnection.newSession(token));
 
         Bundle extras = new Bundle();
         extras.putBoolean(CustomTabsConnection.NO_PRERENDERING_KEY, true);
@@ skipping 374 matching lines @@
         } finally {
             ThreadUtils.runOnUiThreadBlocking(new Runnable() {
                 @Override
                 public void run() {
                     PrefServiceBridge.getInstance().setNetworkPredictionEnabled(enabled);
                 }
             });
         }
     }
 }