Add indication of instrumentation active/inactive to analysis server status.

pkg/analyzer/lib/instrumentation/instrumentation.dart

Index: pkg/analyzer/lib/instrumentation/instrumentation.dart
diff --git a/pkg/analyzer/lib/instrumentation/instrumentation.dart b/pkg/analyzer/lib/instrumentation/instrumentation.dart
index c3a9920bd5a1fa89c2b53cc62a440de245be64a7..2d57d621a838950c701449d75c821bf70cec37d3 100644
--- a/pkg/analyzer/lib/instrumentation/instrumentation.dart
+++ b/pkg/analyzer/lib/instrumentation/instrumentation.dart
@@ -76,6 +76,12 @@ class InstrumentationService {
   InstrumentationService(this._instrumentationServer);
 
   /**
+   * Return true if this [InstrumentationService] was initialized with a

[Brian Wilkerson, 2015/01/13 22:33:29]

nit: "true" --> "`true`", "null" --> "`null`"

[Paul Berry, 2015/01/14 18:23:03]

Done.

+   * non-null server (and hence instrumentation is active).
+   */
+  bool get isActive => _instrumentationServer != null;
+
+  /**
    * The current time, expressed as a decimal encoded number of milliseconds.
    */
   String get _timestamp => new DateTime.now().millisecondsSinceEpoch.toString();
@@ -106,7 +112,8 @@ class InstrumentationService {
   void logFileRead(String path, int modificationTime, String content) {
     if (_instrumentationServer != null) {

[Brian Wilkerson, 2015/01/13 22:33:29]

We should replace existing tests of this form with "isActive".

[Paul Berry, 2015/01/14 18:23:03]

Agreed.  I'll do a follow-up CL.

       String timeStamp = _toString(modificationTime);
-      _instrumentationServer.log(_join([TAG_FILE_READ, path, timeStamp, content]));
+      _instrumentationServer.log(
+          _join([TAG_FILE_READ, path, timeStamp, content]));
     }
   }
 
@@ -117,7 +124,8 @@ class InstrumentationService {
    */
   void logLogEntry(String level, DateTime time, String message) {
     if (_instrumentationServer != null) {
-      String timeStamp = time == null ? 'null' : time.millisecondsSinceEpoch.toString();
+      String timeStamp =
+          time == null ? 'null' : time.millisecondsSinceEpoch.toString();
       _instrumentationServer.log(
           _join([TAG_LOG_ENTRY, level, timeStamp, message]));
     }