Make sure multi chracter codepoints are deleted correctly

content/public/android/javatests/src/org/chromium/content/browser/input/AdapterInputConnectionTest.java

Index: content/public/android/javatests/src/org/chromium/content/browser/input/AdapterInputConnectionTest.java
diff --git a/content/public/android/javatests/src/org/chromium/content/browser/input/AdapterInputConnectionTest.java b/content/public/android/javatests/src/org/chromium/content/browser/input/AdapterInputConnectionTest.java
index deb151ef26215d7e6d26242190e38b6cbe9194c0..9b0f0723a9330dc6c485a5a0eef4f0198c2d45fa 100644
--- a/content/public/android/javatests/src/org/chromium/content/browser/input/AdapterInputConnectionTest.java
+++ b/content/public/android/javatests/src/org/chromium/content/browser/input/AdapterInputConnectionTest.java
@@ -8,6 +8,7 @@ import android.content.Context;
 import android.os.IBinder;
 import android.os.ResultReceiver;
 import android.test.suitebuilder.annotation.MediumTest;
+import android.test.suitebuilder.annotation.SmallTest;
 import android.text.Editable;
 import android.text.Selection;
 import android.view.KeyEvent;
@@ -45,6 +46,23 @@ public class AdapterInputConnectionTest extends ContentShellTestBase {
                 getContentViewCore().getContainerView(), mImeAdapter, mEditable, info);
     }
 
+    @SmallTest
+    @Feature({"TextInput", "Main"})
+    public void testAdjustLengthBeforeAndAfterSelection() throws Throwable {
+        final String ga = "\uAC00";
+        final String smiley = "\uD83D\uDE0A"; // multi character codepoint
+
+        // No need to adjust length.
+        assertFalse(AdapterInputConnection.isIndexBetweenUtf16SurrogatePair("a", 0));
+        assertFalse(AdapterInputConnection.isIndexBetweenUtf16SurrogatePair(ga, 0));
+        assertFalse(AdapterInputConnection.isIndexBetweenUtf16SurrogatePair("aa", 1));
+        assertFalse(AdapterInputConnection.isIndexBetweenUtf16SurrogatePair("a" + smiley + "a", 1));
+
+        // Needs to adjust length.
+        assertTrue(AdapterInputConnection.isIndexBetweenUtf16SurrogatePair(smiley, 1));
+        assertTrue(AdapterInputConnection.isIndexBetweenUtf16SurrogatePair(smiley + "a", 1));
+    }
+
     @MediumTest
     @Feature({"TextInput", "Main"})
     @RerunWithUpdatedContainerView