tracing: Don't report buffer usage for accessibility (android).

Change the message in the recording notification so that it doesn't
show a "0%" buffer usage forever.

Bug: 932769
Change-Id: I193b656ef264147fa62ec8b788dff9720580d756
Reviewed-on: https://chromium-review.googlesource.com/c/1476991
Reviewed-by: Sami Kyöstilä <skyostil@chromium.org>
Commit-Queue: Eric Seckler <eseckler@chromium.org>
Cr-Commit-Position: refs/heads/master@{#633227}

chrome/android/java/src/org/chromium/chrome/browser/tracing/TracingNotificationManager.java

@@ -34,6 +34,8 @@ public class TracingNotificationManager {
 
     // Non-translated strings:
     private static final String MSG_ACTIVE_NOTIFICATION_TITLE = "Chrome trace is being recorded";
+    private static final String MSG_ACTIVE_NOTIFICATION_ACCESSIBILITY_MESSAGE =
+            "Tracing is active.";
     private static final String MSG_ACTIVE_NOTIFICATION_MESSAGE = "Trace buffer usage: %s%%";
     private static final String MSG_STOPPING_NOTIFICATION_TITLE = "Chrome trace is stopping";
     private static final String MSG_STOPPING_NOTIFICATION_MESSAGE =
@@ -103,6 +105,13 @@ public static void showTracingActiveNotification() {
         String message = String.format(
                 MSG_ACTIVE_NOTIFICATION_MESSAGE, sTracingActiveNotificationBufferPercentage);
 
+        // We can't update the notification if accessibility is enabled as this may interfere with
+        // selecting the stop button, so choose a different message.
+        AccessibilityManager am =
+                (AccessibilityManager) context.getSystemService(Context.ACCESSIBILITY_SERVICE);
+        if (am.isEnabled() && am.isTouchExplorationEnabled())
+            message = MSG_ACTIVE_NOTIFICATION_ACCESSIBILITY_MESSAGE;
+
         sTracingActiveNotificationBuilder =
                 createNotificationBuilder()
                         .setContentTitle(title)