customtabs: Run the session cleanup code on the UI thread.

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

Index: chrome/android/javatests/src/org/chromium/chrome/browser/customtabs/CustomTabsConnectionTest.java
diff --git a/chrome/android/javatests/src/org/chromium/chrome/browser/customtabs/CustomTabsConnectionTest.java b/chrome/android/javatests/src/org/chromium/chrome/browser/customtabs/CustomTabsConnectionTest.java
index 96f1d9f97bfcfec2ebd2e31d8918fdb7414b7197..9327531fbded268d3ebd472740f37b7f7fda329d 100644
--- a/chrome/android/javatests/src/org/chromium/chrome/browser/customtabs/CustomTabsConnectionTest.java
+++ b/chrome/android/javatests/src/org/chromium/chrome/browser/customtabs/CustomTabsConnectionTest.java
@@ -13,7 +13,7 @@ import android.support.customtabs.ICustomTabsCallback;
 import android.test.InstrumentationTestCase;
 import android.test.suitebuilder.annotation.SmallTest;
 
-import org.chromium.base.test.util.DisabledTest;
+import org.chromium.base.ThreadUtils;
 
 /** Tests for CustomTabsConnection. */
 public class CustomTabsConnectionTest extends InstrumentationTestCase {
@@ -33,7 +33,16 @@ public class CustomTabsConnectionTest extends InstrumentationTestCase {
     @Override
     protected void tearDown() throws Exception {
         super.tearDown();
-        mCustomTabsConnection.cleanupAll();
+        cleanupSessions();
+    }
+
+    private void cleanupSessions() {
+        ThreadUtils.runOnUiThreadBlocking(new Runnable() {
+            @Override
+            public void run() {
+                mCustomTabsConnection.cleanupAll();
+            }
+        });
     }
 
     /**
@@ -136,7 +145,7 @@ public class CustomTabsConnectionTest extends InstrumentationTestCase {
     @SmallTest
     public void testForgetsSession() {
         ICustomTabsCallback cb = assertWarmupAndMayLaunchUrl(null, URL, true);
-        mCustomTabsConnection.cleanupAll();
+        cleanupSessions();
         assertWarmupAndMayLaunchUrl(cb, URL, false);
     }
 
@@ -194,10 +203,8 @@ public class CustomTabsConnectionTest extends InstrumentationTestCase {
 
     /**
      * Tests that the mayLaunchUrl() throttling is reset after a long enough wait.
-     * @SmallTest
-     * crbug.com/523057
      */
-    @DisabledTest
+    @SmallTest
     public void testThrottlingIsReset() {
         ICustomTabsCallback cb = assertWarmupAndMayLaunchUrl(null, URL, true);
         mCustomTabsConnection.mayLaunchUrl(cb, Uri.parse(URL), null, null);