Cleanup 1: split parts into their own libraries, remove unused imports

pkg/compiler/lib/src/info/send_info.dart

Index: pkg/compiler/lib/src/info/send_info.dart
diff --git a/pkg/compiler/lib/src/info/send_info.dart b/pkg/compiler/lib/src/info/send_info.dart
index 96e0e984320c800d79b497deb61ae238fd6fb794..0c311149301c8f275e2b959cfabbc5e1eb0fb663 100644
--- a/pkg/compiler/lib/src/info/send_info.dart
+++ b/pkg/compiler/lib/src/info/send_info.dart
@@ -5,15 +5,11 @@
 /// Computes measurements about sends in a function.
 library compiler.src.info.send_info;
 
-import 'dart:convert';
-
 import 'package:dart2js_info/src/measurements.dart';
 import 'package:dart2js_info/src/util.dart' show
     recursiveDiagnosticString;
 
 import '../common.dart';
-import '../common/tasks.dart' show
-    CompilerTask;
 import '../compiler.dart' show
     Compiler;
 import '../dart_types.dart';