Add Isolate.current getter, returning the current isolate as an Isolate object.

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 6a2bfb43eace7e641ca6fc260a9a653f37f8ff8d..dbdbd333d8a1ce0c75a0ff54c7b4e32b1c7928c9 100644
--- a/sdk/lib/isolate/isolate.dart
+++ b/sdk/lib/isolate/isolate.dart
@@ -120,6 +120,17 @@ class Isolate {
                              this.terminateCapability});
 
   /**
+   * Return the current isolate.
+   *
+   * This isolate can be sent to other isolates created using [Isolate.spawn]

[floitsch, 2014/12/02 12:13:57]

a: we should agree on terminology for these kind of isolates (and the other
ones). "Local", "same-source", ...

b: I don't think we need to mention this restriction. It's implied by the normal
serialization rules.

c: maybe just add examples instead.

[Lasse Reichstein Nielsen, 2014/12/03 15:34:30]

Removed. Can't think of a short example that isn't entirely contrived.

+   * or its control port and capablities can be sent to isolates created
+   * using [Isolate.spawnUri].
+   * It gives access to the capabilities needed to inspect, pause or kill

[floitsch, 2014/12/02 12:13:56]

New line before?

[Lasse Reichstein Nielsen, 2014/12/03 15:34:30]

Removed the previous paragraph.

+   * the isolate, and allows passing these capabilities to others.
+   */
+  external static Isolate get current;
+
+  /**
    * Creates and spawns an isolate that shares the same code as the current
    * isolate.
    *