Remove Compiler.mainApp and Compiler.mainFunction

pkg/compiler/lib/src/deferred_load.dart

Index: pkg/compiler/lib/src/deferred_load.dart
diff --git a/pkg/compiler/lib/src/deferred_load.dart b/pkg/compiler/lib/src/deferred_load.dart
index 77d9266b5a19fd28d376ec1dcd017154bb4fb5d6..d233398127bc1fcc50a7ee289ba2a9f2067c53cd 100644
--- a/pkg/compiler/lib/src/deferred_load.dart
+++ b/pkg/compiler/lib/src/deferred_load.dart
@@ -791,11 +791,11 @@ class DeferredLoadTask extends CompilerTask {
     compiler.impactStrategy.onImpactUsed(IMPACT_USE);
   }
 
-  void beforeResolution(Compiler compiler) {
-    if (compiler.mainApp == null) return;
+  void beforeResolution(LibraryEntity mainLibrary) {
+    if (mainLibrary == null) return;
     // TODO(johnniwinther): Support deferred load for kernel based elements.
     if (compiler.options.loadFromDill) return;
-    _allDeferredImports[_fakeMainImport] = compiler.mainApp;
+    _allDeferredImports[_fakeMainImport] = mainLibrary;
     var lastDeferred;
     // When detecting duplicate prefixes of deferred libraries there are 4
     // cases of duplicate prefixes:
@@ -855,8 +855,9 @@ class DeferredLoadTask extends CompilerTask {
                   import, MessageKind.DEFERRED_LIBRARY_WITHOUT_PREFIX);
             } else {
               prefixDeferredImport[prefix] = import;
+              Uri mainLibraryUri = compiler.mainLibraryUri;
               _deferredImportDescriptions[key] =
-                  new ImportDescription(import, library, compiler);
+                  new ImportDescription(import, library, mainLibraryUri);
             }
             isProgramSplit = true;
             lastDeferred = import;
@@ -1031,9 +1032,9 @@ class ImportDescription {
   final LibraryElement _importingLibrary;
 
   ImportDescription(
-      ImportElement import, LibraryElement importingLibrary, Compiler compiler)
-      : importingUri = uri_extras.relativize(compiler.mainApp.canonicalUri,
-            importingLibrary.canonicalUri, false),
+      ImportElement import, LibraryElement importingLibrary, Uri mainLibraryUri)
+      : importingUri = uri_extras.relativize(
+            mainLibraryUri, importingLibrary.canonicalUri, false),
         prefix = import.prefix.name,
         _importingLibrary = importingLibrary;