Deprecate automatic generation of precompiled.js.

sdk/lib/_internal/compiler/implementation/dart2js.dart

Index: sdk/lib/_internal/compiler/implementation/dart2js.dart
diff --git a/sdk/lib/_internal/compiler/implementation/dart2js.dart b/sdk/lib/_internal/compiler/implementation/dart2js.dart
index b29364f38b563582e5c6f15f79e9fc242c7e05b4..5d2349deada7037e59ab6b8c5616e33feabfaf71 100644
--- a/sdk/lib/_internal/compiler/implementation/dart2js.dart
+++ b/sdk/lib/_internal/compiler/implementation/dart2js.dart
@@ -297,6 +297,7 @@ Future compile(List<String> argv) {
     new OptionHandler('--disallow-unsafe-eval',
                       (_) => hasDisallowUnsafeEval = true),
     new OptionHandler('--show-package-warnings', passThrough),
+    new OptionHandler('--csp', passThrough),
     new OptionHandler('-D.+=.*', addInEnvironment),
 
     // The following two options must come last.
@@ -575,6 +576,10 @@ Supported options:
   --show-package-warnings
     Show warnings and hints generated from packages.
 
+  --csp
+    Disables dynamic generation of code in the generated output. This is
+    necessary to satisfy CSP restrictions (see http://www.w3.org/TR/CSP/).
+
 The following options are only used for compiler development and may
 be removed in a future version: