Add "checked" parameter to Isolate.spawnUri.

sdk/lib/isolate/isolate.dart

Index: sdk/lib/isolate/isolate.dart
diff --git a/sdk/lib/isolate/isolate.dart b/sdk/lib/isolate/isolate.dart
index 8c46d6047e28c56ae62455f2156588a5935d6d17..ac9a311c583d7db94edac2e1410acd896adab0f0 100644
--- a/sdk/lib/isolate/isolate.dart
+++ b/sdk/lib/isolate/isolate.dart
@@ -172,6 +172,24 @@ class Isolate {
    * When present, the parameter `args` is set to the provided [args] list.
    * When present, the parameter `message` is set to the initial [message].
    *
+   * If the [paused] parameter is set to `true`,
+   * the isolate will start up in a paused state,
+   * as if by an initial call of `isolate.pause(isolate.pauseCapability)`.
+   * This allows setting up error or exit listeners on the isolate
+   * before it starts running.
+   * To resume the isolate, call `isolate.resume(isolate.pauseCapability)`.
+   *
+   * If the [checked] parameter is set to `true` or `false`,
+   * the new isolate will run code in checked mode,
+   * respectively in production mode, if possible.
+   * If the parameter is omitted, the new isolate will inherit the
+   * value from the current isolate.
+   *
+   * If the isolate code was pre-compiled, it may not be possible to change
+   * the checked mode setting dynamically.
+   *
+   * WARNING: The [checked] parameter is not implemented on all platforms yet.

[kevmoo, 2015/06/02 17:42:55]

We have no plan to implement this in dart2js, right?

We should be explicit about which platform it is implemented on and the behavior
on unimplemented platforms – noop?

[Lasse Reichstein Nielsen, 2015/06/03 06:55:25]

We could implement it by appending "?checked" to the URI when fetching the file.
Then the server could potentially send a different file if it has one (or
compile it while we wait, if not in a rush).
Dart2js can decide what to do, but doing nothing is an option.
I prefer not to mention specific implementations in the system libraries. It
doesn't make sense in the long run where there might be dozens of platforms.
Should we mention Sky? Dartium? 
I'd prefer to leave it as this - a platform implements this if it can, otherwise
it may be ignored. I'll add some more text to elaborate that.

+   *
    * If the [packageRoot] parameter is provided, it is used to find the location
    * of packages imports in the spawned isolate.
    * The `packageRoot` URI must be a "file" or "http"/"https" URI that specifies
@@ -187,15 +205,6 @@ class Isolate {
    * WARNING: The [packageRoot] parameter is not implemented on all
    * platforms yet.
    *
-   * If the [paused] parameter is set to `true`,
-   * the isolate will start up in a paused state,
-   * as if by an initial call of `isolate.pause(isolate.pauseCapability)`.
-   * This allows setting up error or exit listeners on the isolate
-   * before it starts running.
-   * To resume the isolate, call `isolate.resume(isolate.pauseCapability)`.
-   *
-   * WARNING: The `pause` parameter is not implemented on all platforms yet.
-   *
    * Returns a future that will complete with an [Isolate] instance if the
    * spawning succeeded. It will complete with an error otherwise.
    */
@@ -204,6 +213,7 @@ class Isolate {
       List<String> args,
       var message,
       {bool paused: false,
+       bool checked,
        Uri packageRoot});
 
   /**