Start AccessibilityUtil#isAccessibilityEnabled trace after early return

Start the trace after the early return to avoid a trace begin without end.

NOTRY=true

Bug: 932356
Change-Id: I07968ee22b41d9b0274ccfcaad6581173a10b020
Reviewed-on: https://chromium-review.googlesource.com/c/1474740Reviewed-by: Theresa <twellington@chromium.org>
Reviewed-by: David Trainor <dtrainor@chromium.org>
Commit-Queue: Theresa <twellington@chromium.org>
Cr-Commit-Position: refs/heads/master@{#632799}

chrome/android/java/src/org/chromium/chrome/browser/util/AccessibilityUtil.java

@@ -57,9 +57,10 @@ public class AccessibilityUtil {
      * @return        Whether or not accessibility and touch exploration are enabled.
      */
     public static boolean isAccessibilityEnabled() {
-        TraceEvent.begin("AccessibilityManager::isAccessibilityEnabled");
         if (sIsAccessibilityEnabled != null) return sIsAccessibilityEnabled;
 
+        TraceEvent.begin("AccessibilityManager::isAccessibilityEnabled");
+
         AccessibilityManager manager =
                 (AccessibilityManager) ContextUtils.getApplicationContext().getSystemService(
                         Context.ACCESSIBILITY_SERVICE);