Fix error initializeEnumMap() is exceeding the 65535 bytes limit (#9954)

During build we hit a the error
>The code of method initializeEnumMap() is exceeding the 65535 bytes
limit.

This gets around the error by splitting the method into as many methods
as needed.

user/src/com/google/web/bindery/autobean/gwt/rebind/AutoBeanFactoryGenerator.java

@@ -63,6 +63,8 @@
  */
 public class AutoBeanFactoryGenerator extends Generator {
 
+  private static final int MAX_ENUMS_PER_METHOD = 2000;
+
   private GeneratorContext context;
   private String simpleSourceName;
   private TreeLogger logger;
@@ -372,14 +374,37 @@ private void writeEnumSetup(SourceWriter sw) {
       list.add(entry.getKey());
     }
 
-    sw.println("@Override protected void initializeEnumMap() {");
-    sw.indent();
+    int methodCount = 0;
+    int enumPerMethodCount = MAX_ENUMS_PER_METHOD + MAX_ENUMS_PER_METHOD;
     for (Map.Entry<JEnumConstant, String> entry : model.getEnumTokenMap().entrySet()) {
+      if (enumPerMethodCount >= MAX_ENUMS_PER_METHOD) {
+        if (methodCount != 0) {
+          sw.outdent();
+          sw.println("}");
+        }
+        enumPerMethodCount = 0;
+        methodCount++;
+        sw.println("private void initializeEnumMap_%d() {", methodCount);
+        sw.indent();
+      }
+
       // enumToStringMap.put(Enum.FOO, "FOO");
       sw.println("enumToStringMap.put(%s.%s, \"%s\");", entry.getKey().getEnclosingType()
           .getQualifiedSourceName(), entry.getKey().getName(), entry.getValue());
+
+      enumPerMethodCount++;
     }
+
     for (Map.Entry<String, List<JEnumConstant>> entry : map.entrySet()) {
+      if (enumPerMethodCount >= MAX_ENUMS_PER_METHOD) {
+        sw.outdent();
+        sw.println("}");
+        enumPerMethodCount = 0;
+        methodCount++;
+        sw.println("private void initializeEnumMap_%d() {", methodCount);
+        sw.indent();
+      }
+
       String listExpr;
       if (entry.getValue().size() == 1) {
         JEnumConstant e = entry.getValue().get(0);
@@ -405,6 +430,19 @@ private void writeEnumSetup(SourceWriter sw) {
         listExpr = sb.toString();
       }
       sw.println("stringsToEnumsMap.put(\"%s\", %s);", entry.getKey(), listExpr);
+
+      enumPerMethodCount += entry.getValue().size();
+    }
+
+    if (methodCount != 0) {
+      sw.outdent();
+      sw.println("}");
+    }
+
+    sw.println("@Override protected void initializeEnumMap() {");
+    sw.indent();
+    for (int i = 1; i <= methodCount; i++) {
+      sw.println("initializeEnumMap_%d();", i);
     }
     sw.outdent();
     sw.println("}");