[ddc] Add pkg/dev_compiler as a dep for compiling SDK

Previously making only a change to pkg/dev_compiler would not
trigger the dart_sdk.js files to be rebuilt.

Change-Id: I9eba1a67269d3cc030901cf155a96f7e9f8dde4f
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/217520
Reviewed-by: Sigmund Cherem <sigmund@google.com>
Commit-Queue: Nicholas Shahan <nshahan@google.com>
diff --git a/utils/dartdevc/BUILD.gn b/utils/dartdevc/BUILD.gn
index 67e0411..da80743 100644
--- a/utils/dartdevc/BUILD.gn
+++ b/utils/dartdevc/BUILD.gn
@@ -302,7 +302,10 @@
   }
 
   prebuilt_dart_action(target_name) {
-    deps = [ platform_dep ]
+    deps = [
+      ":dartdevc_files_stamp",
+      platform_dep,
+    ]
 
     inputs = [ platform_input ]