Switch to faster enter/exit animations for herb tabs.

chrome/android/java/res/anim/activity_close_exit.xml

Index: chrome/android/java/res/anim/activity_close_exit.xml
diff --git a/chrome/android/java/res/anim/activity_close_exit.xml b/chrome/android/java/res/anim/activity_close_exit.xml
new file mode 100644
index 0000000000000000000000000000000000000000..e6094ea0a278c2951768142335d7d1726c046b00
--- /dev/null
+++ b/chrome/android/java/res/anim/activity_close_exit.xml
@@ -0,0 +1,26 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!-- Copyright 2016 The Chromium Authors. All rights reserved.
+
+     Use of this source code is governed by a BSD-style license that can be
+     found in the LICENSE file.
+-->
+
+<set xmlns:android="http://schemas.android.com/apk/res/android"
+        android:shareInterpolator="false"
+        android:zAdjustment="top">
+    <alpha android:fromAlpha="1.0"
+            android:toAlpha="0.0"
+            android:interpolator="@android:interpolator/linear"
+            android:fillEnabled="true"
+            android:fillBefore="false"
+            android:fillAfter="true"
+            android:startOffset="100"
+            android:duration="150"/>
+    <translate android:fromYDelta="0%"
+            android:toYDelta="8%"
+            android:fillEnabled="true"
+            android:fillBefore="true"
+            android:fillAfter="true"
+            android:interpolator="@anim/accelerate_quart"
+            android:duration="250"/>
+</set>