Examine widget hierarchy to find clocks.

When switching to a widget, examine its hierarchy to determine if it
contains TextClocks that show hour and minute for the local timezone.
If so, hide the status bar clock.  Doesn't fix closing walls.

Bug: 7667638
Change-Id: I1e2c40345c9e5eb0193efd70838c7ca9f779190b
diff --git a/core/java/android/widget/TextClock.java b/core/java/android/widget/TextClock.java
index 290d9b5..5bf21c0 100644
--- a/core/java/android/widget/TextClock.java
+++ b/core/java/android/widget/TextClock.java
@@ -386,6 +386,16 @@
     }
 
     /**
+     * Returns the current format string. Always valid after constructor has
+     * finished, and will never be {@code null}.
+     *
+     * @hide
+     */
+    public CharSequence getFormat() {
+        return mFormat;
+    }
+
+    /**
      * Selects either one of {@link #getFormat12Hour()} or {@link #getFormat24Hour()}
      * depending on whether the user has selected 24-hour format.
      *