Expose compilerInfo and checkRevision as APIs

Fixes #656

lib/handlebars/compiler/javascript-compiler.js

@@ -32,6 +32,12 @@ JavaScriptCompiler.prototype = {
     }
   },
 
+  compilerInfo: function() {
+    var revision = COMPILER_REVISION,
+        versions = REVISION_CHANGES[revision];
+    return "this.compilerInfo = ["+revision+",'"+versions+"'];\n";
+  },
+
   appendToBuffer: function(string) {
     if (this.environment.isSimple) {
       return "return " + string + ";";
@@ -165,9 +171,7 @@ JavaScriptCompiler.prototype = {
     var source = this.mergeSource();
 
     if (!this.isChild) {
-      var revision = COMPILER_REVISION,
-          versions = REVISION_CHANGES[revision];
-      source = "this.compilerInfo = ["+revision+",'"+versions+"'];\n"+source;
+      source = this.compilerInfo()+source;
     }
 
     if (asObject) {

lib/handlebars/runtime.js

@@ -2,7 +2,7 @@ module Utils from "./utils";
 import Exception from "./exception";
 import { COMPILER_REVISION, REVISION_CHANGES } from "./base";
 
-function checkRevision(compilerInfo) {
+export function checkRevision(compilerInfo) {
   var compilerRevision = compilerInfo && compilerInfo[0] || 1,
       currentRevision = COMPILER_REVISION;
 
@@ -89,7 +89,7 @@ export function template(templateSpec, env) {
           options.data);
 
     if (!options.partial) {
-      checkRevision(container.compilerInfo);
+      env.VM.checkRevision(container.compilerInfo);
     }
 
     return result;