[dart2js] Use deferred reads for standalone dump info.

Change-Id: I43492255a1d9db67a95a1c3ed347640d5e66bbc3
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/363542
Commit-Queue: Nate Biggs <[email protected]>
Reviewed-by: Mayank Patke <[email protected]>

Author: natebiggs

pkg/compiler/lib/src/compiler.dart

@@ -626,10 +626,7 @@ class Compiler {
 
   bool get shouldStopAfterCodegen => stage.shouldWriteCodegen;
 
-  // Only use deferred reads for the linker phase as most deferred entities will
-  // not be needed. In other phases we use most of this data so it's not worth
-  // deferring.
-  bool get useDeferredSourceReads => stage == CompilerStage.jsEmitter;
+  bool get useDeferredSourceReads => stage.shouldUseDeferredSourceReads;
 
   Future<void> runSequentialPhases() async {
     // Load kernel.

pkg/compiler/lib/src/options.dart

@@ -101,6 +101,12 @@ enum CompilerStage {
   bool get shouldWriteGlobalInference => this == CompilerStage.globalInference;
   bool get shouldWriteCodegen => this == CompilerStage.codegenSharded;
 
+  // Only use deferred reads for the linker and dump info phase as most deferred
+  // entities will not be needed. In other phases we use most of this data so
+  // it's not worth deferring.
+  bool get shouldUseDeferredSourceReads =>
+      this == CompilerStage.jsEmitter || this == CompilerStage.dumpInfo;
+
   String get toFlag => _stageFlag;
 
   static String get validFlagValuesString {