Revert last 4 commits by lrn@

pkg/compiler/lib/src/diagnostics/messages.dart

Index: pkg/compiler/lib/src/diagnostics/messages.dart
diff --git a/pkg/compiler/lib/src/diagnostics/messages.dart b/pkg/compiler/lib/src/diagnostics/messages.dart
index 45001eabb5fbef9e205a8bfbe4e7f6f836f5531d..751ffe73f3af36d6ee4fcae4281157b17cee748e 100644
--- a/pkg/compiler/lib/src/diagnostics/messages.dart
+++ b/pkg/compiler/lib/src/diagnostics/messages.dart
@@ -292,7 +292,6 @@ enum MessageKind {
   LIBRARY_NOT_FOUND,
   LIBRARY_NOT_SUPPORTED,
   LIBRARY_TAG_MUST_BE_FIRST,
-  LIBRARY_URI_MISMATCH,
   MAIN_HAS_PART_OF,
   MAIN_NOT_A_FUNCTION,
   MAIN_WITH_EXTRA_PARAMETER,
@@ -2078,26 +2077,6 @@ part of lib.bar;
             }
           ]),
 
-      MessageKind.LIBRARY_URI_MISMATCH: const MessageTemplate(
-          MessageKind.LIBRARY_URI_MISMATCH,
-          "Expected URI of library '#{libraryUri}'.",
-          howToFix: "Try changing the directive to 'part of "
-                    "\"#{libraryUri}\";'.",
-          examples: const [
-            const {
-              'main.dart': """
-library lib.foo;
-
-part 'part.dart';
-
-main() {}
-""",
-              'part.dart': """
-part of 'not-main.dart';
-"""
-            }
-          ]),
-
       MessageKind.MISSING_LIBRARY_NAME: const MessageTemplate(
           MessageKind.MISSING_LIBRARY_NAME,
           "Library has no name. Part directive expected library name "