Return void in zoomBy plumbing to match zoomBy public API

android_webview/javatests/src/org/chromium/android_webview/test/AwZoomTest.java

Index: android_webview/javatests/src/org/chromium/android_webview/test/AwZoomTest.java
diff --git a/android_webview/javatests/src/org/chromium/android_webview/test/AwZoomTest.java b/android_webview/javatests/src/org/chromium/android_webview/test/AwZoomTest.java
index 50d978c657bcf40f44694afe64966533c7f2a943..e6d91fef99c5695a4cb20da26c8995416e395002 100644
--- a/android_webview/javatests/src/org/chromium/android_webview/test/AwZoomTest.java
+++ b/android_webview/javatests/src/org/chromium/android_webview/test/AwZoomTest.java
@@ -120,12 +120,12 @@ public class AwZoomTest extends AwTestBase {
 
     private void zoomByOnUiThreadAndWait(final float delta) throws Throwable {
         final float previousScale = getPixelScaleOnUiThread(mAwContents);
-        assertTrue(runTestOnUiThreadAndGetResult(new Callable<Boolean>() {
+        ThreadUtils.runOnUiThreadBlocking(new Runnable() {
             @Override
-            public Boolean call() throws Exception {
-                return mAwContents.zoomBy(delta);
+            public void run() {
+                mAwContents.zoomBy(delta);
             }
-        }));
+        });
         // The zoom level is updated asynchronously.
         waitForScaleChange(previousScale);
     }