Add waitUntilHasValue() to simplify usage.

android_webview/javatests/src/org/chromium/android_webview/test/util/JSUtils.java

Index: android_webview/javatests/src/org/chromium/android_webview/test/util/JSUtils.java
diff --git a/android_webview/javatests/src/org/chromium/android_webview/test/util/JSUtils.java b/android_webview/javatests/src/org/chromium/android_webview/test/util/JSUtils.java
index 09264bca0029ea4b59cc8da1c7af6e7f850e052d..96455177a0bf809a781752e0494b26f872f434d4 100644
--- a/android_webview/javatests/src/org/chromium/android_webview/test/util/JSUtils.java
+++ b/android_webview/javatests/src/org/chromium/android_webview/test/util/JSUtils.java
@@ -61,7 +61,6 @@ public class JSUtils {
             final AwContents awContents,
             final OnEvaluateJavaScriptResultHelper onEvaluateJavaScriptResultHelper,
             final String code) throws Throwable {
-        int currentCallCount = onEvaluateJavaScriptResultHelper.getCallCount();
         testCase.getInstrumentation().runOnMainSync(new Runnable() {
             @Override
             public void run() {
@@ -69,7 +68,7 @@ public class JSUtils {
                         awContents.getContentViewCore(), code);
             }
         });
-        onEvaluateJavaScriptResultHelper.waitForCallback(currentCallCount);
+        onEvaluateJavaScriptResultHelper.waitUntilHasValue();
         Assert.assertTrue("Failed to retrieve JavaScript evaluation results.",
                 onEvaluateJavaScriptResultHelper.hasValue());
         return onEvaluateJavaScriptResultHelper.getJsonResultAndClear();