Add the --build-summary-exclude-informative flag.

pkg/analyzer_cli/lib/src/build_mode.dart

Index: pkg/analyzer_cli/lib/src/build_mode.dart
diff --git a/pkg/analyzer_cli/lib/src/build_mode.dart b/pkg/analyzer_cli/lib/src/build_mode.dart
index 4111aefabb9099319a2c76f03f12da700d6735ea..0c20851589ee8c43d5becac6fd2fab4e8a82428c 100644
--- a/pkg/analyzer_cli/lib/src/build_mode.dart
+++ b/pkg/analyzer_cli/lib/src/build_mode.dart
@@ -94,6 +94,10 @@ class BuildMode {
       }
       // Write the whole package bundle.
       PackageBundleBuilder sdkBundle = assembler.assemble();
+      if (options.buildSummaryExcludeInformative) {
+        sdkBundle.flushInformative();
+        sdkBundle.unlinkedUnitHashes = null;
+      }
       io.File file = new io.File(options.buildSummaryOutput);
       file.writeAsBytesSync(sdkBundle.toBuffer(), mode: io.FileMode.WRITE_ONLY);
     }