Add a content-security-policy (CSP) flag.

lib/compiler/implementation/compiler.dart

Index: lib/compiler/implementation/compiler.dart
diff --git a/lib/compiler/implementation/compiler.dart b/lib/compiler/implementation/compiler.dart
index 62d1d9976218de87434e65d39d30f8797f703ae9..919e7f7fe4b1304015d14c1b41e9f648af89ed95 100644
--- a/lib/compiler/implementation/compiler.dart
+++ b/lib/compiler/implementation/compiler.dart
@@ -201,6 +201,7 @@ abstract class Compiler implements DiagnosticListener {
             this.enableMinification: false,
             bool emitJavaScript: true,
             bool generateSourceMap: true,
+            bool enableContentSecurityPolicy: false,
             List<String> strips: const []})
       : libraries = new Map<String, LibraryElement>(),
         progress = new Stopwatch() {
@@ -217,7 +218,9 @@ abstract class Compiler implements DiagnosticListener {
     checker = new TypeCheckerTask(this);
     typesTask = new ti.TypesTask(this, enableConcreteTypeInference);
     backend = emitJavaScript ?
-        new js_backend.JavaScriptBackend(this, generateSourceMap) :
+        new js_backend.JavaScriptBackend(this,
+                                         generateSourceMap,
+                                         enableContentSecurityPolicy) :
         new dart_backend.DartBackend(this, strips);
     constantHandler = new ConstantHandler(this, backend.constantSystem);
     enqueuer = new EnqueueTask(this);