From a8d9dbf110496075617b956654894cf3e7f0d190 Mon Sep 17 00:00:00 2001
From: Alex Rickabaugh <alx+alxhub@alxandria.net>
Date: Sun, 8 Nov 2015 21:56:52 -0800
Subject: [PATCH] feat(dart): Support forcing dev mode via enableDevMode in
 Dart.

Closes #5193
---
 modules/angular2/src/core/dev_mode.dart |  1 -
 modules/angular2/src/facade/lang.dart   | 15 ++++++++++++---
 2 files changed, 12 insertions(+), 4 deletions(-)
 delete mode 100644 modules/angular2/src/core/dev_mode.dart

diff --git a/modules/angular2/src/core/dev_mode.dart b/modules/angular2/src/core/dev_mode.dart
deleted file mode 100644
index ad6c2091ea..0000000000
--- a/modules/angular2/src/core/dev_mode.dart
+++ /dev/null
@@ -1 +0,0 @@
-// Dart development mode is determined by checked mode.
\ No newline at end of file
diff --git a/modules/angular2/src/facade/lang.dart b/modules/angular2/src/facade/lang.dart
index ba3c5c71ba..3353bfddbd 100644
--- a/modules/angular2/src/facade/lang.dart
+++ b/modules/angular2/src/facade/lang.dart
@@ -225,18 +225,27 @@ bool isJsObject(o) {
   return false;
 }
 
+bool _forceDevMode = false;
+bool _devModeLocked = false;
+
 void lockDevMode() {
-  // lockDevMode() has no effect in Dart.
+  _devModeLocked = true;
 }
 
 void enableDevMode() {
-  // enableDevMode() has no effect in Dart.
+  if (_forceDevMode) {
+    return;
+  }
+  if (_devModeLocked) {
+    throw new Exception("Cannot enable dev mode after platform setup.");
+  }
+  _forceDevMode = true;
 }
 
 bool assertionsEnabled() {
   var k = false;
   assert((k = true));
-  return k;
+  return _forceDevMode || k;
 }
 
 // Can't be all uppercase as our transpiler would think it is a special directive...