[Android] Reduce visibility of Tab#getTabObservers.

chrome/android/java/src/org/chromium/chrome/browser/tab/Tab.java

Index: chrome/android/java/src/org/chromium/chrome/browser/tab/Tab.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/tab/Tab.java b/chrome/android/java/src/org/chromium/chrome/browser/tab/Tab.java
index d66c51042af0e6e5656f349585d95fce9f7c7139..5a1613f510729edd649680349dfac614e3232afe 100644
--- a/chrome/android/java/src/org/chromium/chrome/browser/tab/Tab.java
+++ b/chrome/android/java/src/org/chromium/chrome/browser/tab/Tab.java
@@ -1201,7 +1201,7 @@ public class Tab implements ViewGroup.OnHierarchyChangeListener,
      *         {@link java.util.Iterator#remove()} will throw an
      *         {@link UnsupportedOperationException}.
      */
-    public ObserverList.RewindableIterator<TabObserver> getTabObservers() {
+    protected ObserverList.RewindableIterator<TabObserver> getTabObservers() {
         return mObservers.rewindableIterator();
     }