Implement modular compilation

tool/build_sdk.sh

Index: tool/build_sdk.sh
diff --git a/tool/build_sdk.sh b/tool/build_sdk.sh
index cdf1a3ff0528804e710754665fe30a88c8a4c53a..7166df0e82c908c00e33bb78bd90bbe3e5716016 100755
--- a/tool/build_sdk.sh
+++ b/tool/build_sdk.sh
@@ -8,13 +8,15 @@ dart -c tool/patch_sdk.dart tool/input_sdk tool/generated_sdk
 
 echo "*** Compiling SDK to JavaScript"
 
-# TODO(ochafik): Re-enable named params destructuring when Atom supports it
-# (see https://github.com/dart-lang/dev_compiler/issues/396)
-dart bin/dartdevc.dart --force-compile --no-source-maps --sdk-check \
-    -l warning --dart-sdk tool/generated_sdk -o lib/runtime/ \
-    --no-destructure-named-params \
-    "$@" \
-    dart:_runtime \
-    dart:_debugger \
-    dart:js dart:mirrors dart:html \
-    > tool/sdk_expected_errors.txt || true
+# TODO(jmesserly): break out dart:html & friends.
+#
+# Right now we can't summarize our SDK, so we can't treat it as a normal
+# explicit input (instead we're implicitly compiling against the user's SDK).
+#
+# Another possible approach is to hard code the dart:* library->module mapping
+# into the compiler itself, so it can emit the correct import.
+#
+dart -c tool/build_sdk.dart \
+    --dart-sdk tool/generated_sdk \
+    -o lib/runtime/dart_sdk.js \
+    "$@" > tool/sdk_expected_errors.txt