Removes GWTTestCase.supportsAsync.

GWTTestCase.supportsAsync was just another artifact of Benchmark infra that we recently got rid of.

Change-Id: Ie35e94f8ada80d9e4ae0945199831db6d01cc4a4
diff --git a/tools/api-checker/config/gwt25_26userApi.conf b/tools/api-checker/config/gwt25_26userApi.conf
index c2e5f4f..6c2261a 100644
--- a/tools/api-checker/config/gwt25_26userApi.conf
+++ b/tools/api-checker/config/gwt25_26userApi.conf
@@ -150,6 +150,7 @@
 
 # Removed deprecated benchmark infra
 com.google.gwt.benchmarks.client MISSING
+com.google.gwt.junit.client.GWTTestCase::supportsAsync() MISSING
 
 # Split BaseListenerWrapper
 com.google.gwt.user.client.BaseListenerWrapper::getSource(Lcom/google/gwt/event/shared/GwtEvent;) MISSING
diff --git a/user/src/com/google/gwt/junit/client/GWTTestCase.java b/user/src/com/google/gwt/junit/client/GWTTestCase.java
index 4f88df7..b4deab1 100644
--- a/user/src/com/google/gwt/junit/client/GWTTestCase.java
+++ b/user/src/com/google/gwt/junit/client/GWTTestCase.java
@@ -435,14 +435,6 @@
   }
 
   /**
-   * Returns true if this test case supports asynchronous mode. By default, this
-   * is set to true.
-   */
-  protected boolean supportsAsync() {
-    return true;
-  }
-
-  /**
    * This method has been made final to prevent you from accidentally running
    * client code outside of the GWT environment. Please override
    * {@link #gwtTearDown()} instead.
diff --git a/user/super/com/google/gwt/junit/translatable/com/google/gwt/junit/client/GWTTestCase.java b/user/super/com/google/gwt/junit/translatable/com/google/gwt/junit/client/GWTTestCase.java
index 56464a5..9fdaa9f 100644
--- a/user/super/com/google/gwt/junit/translatable/com/google/gwt/junit/client/GWTTestCase.java
+++ b/user/super/com/google/gwt/junit/translatable/com/google/gwt/junit/client/GWTTestCase.java
@@ -156,43 +156,33 @@
   }
 
   protected final void delayTestFinish(int timeoutMillis) {
-    if (supportsAsync()) {
-      if (timer != null) {
-        // Cancel the pending timer
-        timer.cancel();
-      }
-
-      // Set a new timer for the specified new timeout
-      timer = new KillTimer(timeoutMillis);
-    } else {
-      throw new UnsupportedOperationException(
-          "This test case does not support asynchronous mode.");
+    if (timer != null) {
+      // Cancel the pending timer
+      timer.cancel();
     }
+
+    // Set a new timer for the specified new timeout
+    timer = new KillTimer(timeoutMillis);
   }
 
   protected final void finishTest() {
-    if (supportsAsync()) {
-      if (testIsFinished) {
-        // This test is totally done already, just ignore the call.
-        return;
-      }
+    if (testIsFinished) {
+      // This test is totally done already, just ignore the call.
+      return;
+    }
 
-      if (timer == null) {
-        throw new IllegalStateException(
-            "This test is not in asynchronous mode; call delayTestFinish() first");
-      }
+    if (timer == null) {
+      throw new IllegalStateException(
+          "This test is not in asynchronous mode; call delayTestFinish() first");
+    }
 
-      if (mainTestHasRun) {
-        // This is a correct, successful async finish.
-        reportResultsAndRunNextMethod(null);
-      } else {
-        // The user tried to finish the test before the main body returned!
-        // Just let the test continue running normally.
-        resetAsyncState();
-      }
+    if (mainTestHasRun) {
+      // This is a correct, successful async finish.
+      reportResultsAndRunNextMethod(null);
     } else {
-      throw new UnsupportedOperationException(
-          "This test case does not support asynchronous mode.");
+      // The user tried to finish the test before the main body returned!
+      // Just let the test continue running normally.
+      resetAsyncState();
     }
   }
 
@@ -237,10 +227,6 @@
     }
   }
 
-  protected boolean supportsAsync() {
-    return true;
-  }
-
   private void assertTestState() {
     // TODO(goktug): Add assertTestState to other calls (e.g. delayTestFinish)
     // TODO(goktug): Report any problems via GWTRunner.