[Android] Add reinitiate() to ObserverList's iterator.

If we need to iterate an ObserverList multiple times, we can avoid iterator object
reallocation by using this reinitiate() method.

BUG=273217

Review URL: https://chromiumcodereview.appspot.com/22824044

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@221105 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 40 insertions, 0 deletions

diff --git a/base/android/javatests/src/org/chromium/base/ObserverListTest.java b/base/android/javatests/src/org/chromium/base/ObserverListTest.java
index 10c898c..8a17445 100644
--- a/base/android/javatests/src/org/chromium/base/ObserverListTest.java
+++ b/base/android/javatests/src/org/chromium/base/ObserverListTest.java
@@ -7,6 +7,7 @@ package org.chromium.base;
 import android.test.InstrumentationTestCase;
 import android.test.suitebuilder.annotation.SmallTest;
 
+import org.chromium.base.ObserverList;
 import org.chromium.base.test.util.Feature;
 
 import java.lang.Iterable;
@@ -177,4 +178,43 @@ public class ObserverListTest extends InstrumentationTestCase {
         }
         assertTrue(noElementExceptionThrown);
     }
+
+    @SmallTest
+    @Feature({"Android-AppBase"})
+    public void testRewindableIterator() {
+        ObserverList<Integer> observerList = new ObserverList<Integer>();
+        observerList.addObserver(5);
+        observerList.addObserver(10);
+        observerList.addObserver(15);
+        assertEquals(3, getSizeOfIterable(observerList));
+
+        ObserverList.RewindableIterator<Integer> it = observerList.rewindableIterator();
+        assertTrue(it.hasNext());
+        assertTrue(5 == it.next());
+        assertTrue(it.hasNext());
+        assertTrue(10 == it.next());
+        assertTrue(it.hasNext());
+        assertTrue(15 == it.next());
+        assertFalse(it.hasNext());
+
+        it.rewind();
+
+        assertTrue(it.hasNext());
+        assertTrue(5 == it.next());
+        assertTrue(it.hasNext());
+        assertTrue(10 == it.next());
+        assertTrue(it.hasNext());
+        assertTrue(15 == it.next());
+        assertEquals(5, (int) observerList.mObservers.get(0));
+        observerList.removeObserver(5);
+        assertEquals(null, observerList.mObservers.get(0));
+
+        it.rewind();
+
+        assertEquals(10, (int) observerList.mObservers.get(0));
+        assertTrue(it.hasNext());
+        assertTrue(10 == it.next());
+        assertTrue(it.hasNext());
+        assertTrue(15 == it.next());
+    }
 }