ChangeQueryBuilder: Move Change-Id pattern string to Change class

So that it can be reused.

Note that we can't precompile the patten here because it's referenced
from GWT where java.util.regex.Pattern is not available.

Change-Id: I793dffa9bac12e5d9b8ab341c04c04a7e2ee0f6b

gerrit-reviewdb/src/main/java/com/google/gerrit/reviewdb/client/Change.java

diff --git a/gerrit-reviewdb/src/main/java/com/google/gerrit/reviewdb/client/Change.java b/gerrit-reviewdb/src/main/java/com/google/gerrit/reviewdb/client/Change.java
index 20f9b82..1864c56 100644
--- a/gerrit-reviewdb/src/main/java/com/google/gerrit/reviewdb/client/Change.java
+++ b/gerrit-reviewdb/src/main/java/com/google/gerrit/reviewdb/client/Change.java
@@ -280,6 +280,9 @@
   /** ID number of the first patch set in a change. */
   public static final int INITIAL_PATCH_SET_ID = 1;
 
+  /** Change-Id pattern. */
+  public static final String CHANGE_ID_PATTERN = "^[iI][0-9a-f]{4,}.*$";
+
   /**
    * Current state within the basic workflow of the change.
    *

gerrit-server/src/main/java/com/google/gerrit/server/query/change/ChangeQueryBuilder.java

diff --git a/gerrit-server/src/main/java/com/google/gerrit/server/query/change/ChangeQueryBuilder.java b/gerrit-server/src/main/java/com/google/gerrit/server/query/change/ChangeQueryBuilder.java
index d92c2b2..590be32 100644
--- a/gerrit-server/src/main/java/com/google/gerrit/server/query/change/ChangeQueryBuilder.java
+++ b/gerrit-server/src/main/java/com/google/gerrit/server/query/change/ChangeQueryBuilder.java
@@ -14,6 +14,7 @@
 
 package com.google.gerrit.server.query.change;
 
+import static com.google.gerrit.reviewdb.client.Change.CHANGE_ID_PATTERN;
 import static com.google.gerrit.server.query.change.ChangeData.asChanges;
 
 import com.google.common.annotations.VisibleForTesting;
@@ -94,8 +95,7 @@
   }
 
   private static final Pattern PAT_LEGACY_ID = Pattern.compile("^[1-9][0-9]*$");
-  private static final Pattern PAT_CHANGE_ID =
-      Pattern.compile("^[iI][0-9a-f]{4,}.*$");
+  private static final Pattern PAT_CHANGE_ID = Pattern.compile(CHANGE_ID_PATTERN);
   private static final Pattern DEF_CHANGE = Pattern.compile(
       "^(?:[1-9][0-9]*|(?:[^~]+~[^~]+~)?[iI][0-9a-f]{4,}.*)$");