Implement MethodMirror.location in the VM.

sdk/lib/mirrors/mirrors.dart

Index: sdk/lib/mirrors/mirrors.dart
diff --git a/sdk/lib/mirrors/mirrors.dart b/sdk/lib/mirrors/mirrors.dart
index 18669690a569ed71750e16df66d2b256cbd9889e..ddffcd67a23200f3a791912d6a797cf703b500db 100644
--- a/sdk/lib/mirrors/mirrors.dart
+++ b/sdk/lib/mirrors/mirrors.dart
@@ -1083,6 +1083,24 @@ abstract class ParameterMirror implements VariableMirror {
  * A [SourceLocation] describes the span of an entity in Dart source code.
  */
 abstract class SourceLocation {
+  /**
+   * The 1-based line number for this source location.
+   *
+   * A value of 0 means that the line number is unknown.
+   */
+  int get line;
+
+  /**
+   * The 1-based column number for this source location.
+   *
+   * A value of 0 means that the column number is unknown.
+   */
+  int get column;
+
+  /**
+   * Returns the URI where the source originated.
+   */
+  Uri get sourceUri;
 }
 
 /**