From 5ba47eb42be2c49b78c6b0492021ce8e78387d3f Mon Sep 17 00:00:00 2001
From: Shawn Pearce <sop@google.com>
Date: Fri, 2 Jan 2015 19:26:21 -0500
Subject: [PATCH] ChangeScreen2: Preload CodeMirror CSS and JS

The JavaScript library for CodeMirror is several hundred KiBs.
Although it does not change often and can be cached by browsers
preloading while the user is looking at a change helps to hide
any latency.

Change-Id: I43fecd297983e26472030a412fde5c9d98491adb
---
 .../java/com/google/gerrit/client/change/ChangeScreen2.java  | 3 +++
 .../src/main/java/net/codemirror/lib/CodeMirror.java         | 5 +++++
 2 files changed, 8 insertions(+)

diff --git a/gerrit-gwtui/src/main/java/com/google/gerrit/client/change/ChangeScreen2.java b/gerrit-gwtui/src/main/java/com/google/gerrit/client/change/ChangeScreen2.java
index 45194e2637..5d6fa380bc 100644
--- a/gerrit-gwtui/src/main/java/com/google/gerrit/client/change/ChangeScreen2.java
+++ b/gerrit-gwtui/src/main/java/com/google/gerrit/client/change/ChangeScreen2.java
@@ -91,6 +91,8 @@ import com.google.gwtexpui.globalkey.client.KeyCommandSet;
 import com.google.gwtexpui.safehtml.client.SafeHtmlBuilder;
 import com.google.gwtorm.client.KeyUtil;
 
+import net.codemirror.lib.CodeMirror;
+
 import java.sql.Timestamp;
 import java.util.ArrayList;
 import java.util.EnumSet;
@@ -511,6 +513,7 @@ public class ChangeScreen2 extends Screen {
     }
 
     ChangeGlue.fireShowChange(changeInfo, changeInfo.revision(revision));
+    CodeMirror.preload();
     startPoller();
     if (NewChangeScreenBar.show()) {
       add(new NewChangeScreenBar(changeId));
diff --git a/gerrit-gwtui/src/main/java/net/codemirror/lib/CodeMirror.java b/gerrit-gwtui/src/main/java/net/codemirror/lib/CodeMirror.java
index 8255cbb50f..c6e106338c 100644
--- a/gerrit-gwtui/src/main/java/net/codemirror/lib/CodeMirror.java
+++ b/gerrit-gwtui/src/main/java/net/codemirror/lib/CodeMirror.java
@@ -15,6 +15,7 @@
 package net.codemirror.lib;
 
 import com.google.gerrit.client.diff.DisplaySide;
+import com.google.gerrit.client.rpc.CallbackGroup;
 import com.google.gwt.core.client.JavaScriptObject;
 import com.google.gwt.dom.client.Element;
 import com.google.gwt.dom.client.NativeEvent;
@@ -28,6 +29,10 @@ import net.codemirror.lib.TextMarker.FromTo;
  * @see <a href="http://codemirror.net/doc/manual.html#api">CodeMirror API</a>
  */
 public class CodeMirror extends JavaScriptObject {
+  public static void preload() {
+    initLibrary(CallbackGroup.<Void> emptyCallback());
+  }
+
   public static void initLibrary(AsyncCallback<Void> cb) {
     Loader.initLibrary(cb);
   }