Fix most warnings and other minor cleanups.

lib/compiler/implementation/scanner/scanner_bench.dart

Index: lib/compiler/implementation/scanner/scanner_bench.dart
diff --git a/lib/compiler/implementation/scanner/scanner_bench.dart b/lib/compiler/implementation/scanner/scanner_bench.dart
index 20e7b2d47b3c07ecc8483d88afde46ac34c0e59a..a33e94b15c17c0d68ce5fb2afdc8fad53453a8d8 100644
--- a/lib/compiler/implementation/scanner/scanner_bench.dart
+++ b/lib/compiler/implementation/scanner/scanner_bench.dart
@@ -33,8 +33,8 @@ class ScannerBench {
       }
       timer.stop();
       bar.recordScore(charCount / timer.elapsedInMs());
-      log("Tokenized ${arguments.length} files " +
-          "(total size = ${charCount} chars) " +
+      log("Tokenized ${arguments.length} files "
+          "(total size = ${charCount} chars) "
           "in ${timer.elapsedInMs()}ms");
     }
     bar.end();