Use JsStrategy, remove KernelBackendStrategy

pkg/compiler/lib/src/kernel/element_map_impl.dart

Index: pkg/compiler/lib/src/kernel/element_map_impl.dart
diff --git a/pkg/compiler/lib/src/kernel/element_map_impl.dart b/pkg/compiler/lib/src/kernel/element_map_impl.dart
index f938dc25a9ce1740899388bb0dbfe183498ddbc6..d53af0c39545bb72400800fb56b41c42b758088e 100644
--- a/pkg/compiler/lib/src/kernel/element_map_impl.dart
+++ b/pkg/compiler/lib/src/kernel/element_map_impl.dart
@@ -965,15 +965,26 @@ abstract class KElementCreatorMixin implements ElementCreatorMixin {
 
 /// Implementation of [KernelToElementMapForImpact] that only supports world
 /// impact computation.
-// TODO(johnniwinther): Merge this with [KernelToElementMapForImpactImpl] when
-// [JsStrategy] is the default.
-abstract class KernelToElementMapForImpactImpl
-    implements
-        KernelToElementMapBase,
-        KernelToElementMapForImpact,
-        KernelToElementMapForImpactMixin {
+class KernelToElementMapForImpactImpl extends KernelToElementMapBase
+    with
+        KernelToElementMapForImpactMixin,
+        ElementCreatorMixin,
+        KElementCreatorMixin {
   native.BehaviorBuilder _nativeBehaviorBuilder;
 
+  KernelToElementMapForImpactImpl(
+      DiagnosticReporter reporter, Environment environment)
+      : super(reporter, environment);
+
+  @override
+  bool checkFamily(Entity entity) {
+    assert(
+        '$entity'.startsWith(kElementPrefix),
+        failedAt(entity,
+            "Unexpected entity $entity, expected family $kElementPrefix."));
+    return true;
+  }
+
   /// Adds libraries in [program] to the set of libraries.
   ///
   /// The main method of the first program is used as the main method for the
@@ -1000,121 +1011,6 @@ abstract class KernelToElementMapForImpactImpl
   }
 }
 
-/// Implementation of [KernelToElementMapForImpact] that only supports world
-/// impact computation.
-// TODO(johnniwinther): Merge this with [KernelToElementMapForImpactImpl] when
-// [JsStrategy] is the default.
-class KernelToElementMapForImpactImpl2 extends KernelToElementMapBase
-    with
-        KernelToElementMapForImpactMixin,
-        KernelToElementMapForImpactImpl,
-        ElementCreatorMixin,
-        KElementCreatorMixin {
-  KernelToElementMapForImpactImpl2(
-      DiagnosticReporter reporter, Environment environment)
-      : super(reporter, environment);
-
-  @override
-  bool checkFamily(Entity entity) {
-    assert(
-        '$entity'.startsWith(kElementPrefix),
-        failedAt(entity,
-            "Unexpected entity $entity, expected family $kElementPrefix."));
-    return true;
-  }
-}
-
-/// Mixin for implementing [KernelToElementMapForBuilding] shared between
-/// classes that extend [KernelToElementMapBase], i.e. not [KernelAstAdapter].
-abstract class KernelToElementMapForBuildingFromBaseMixin
-    implements KernelToElementMapForBuilding, KernelToElementMapBase {
-  @override
-  ConstantValue getFieldConstantValue(ir.Field field) {
-    // TODO(johnniwinther): Cache the result in [FieldData].
-    return getConstantValue(field.initializer,
-        requireConstant: field.isConst, implicitNull: !field.isConst);
-  }
-
-  bool hasConstantFieldInitializer(covariant IndexedField field) {
-    FieldData data = _memberData[field.memberIndex];
-    return getFieldConstantValue(data.node) != null;
-  }
-
-  ConstantValue getConstantFieldInitializer(covariant IndexedField field) {
-    FieldData data = _memberData[field.memberIndex];
-    ConstantValue value = getFieldConstantValue(data.node);
-    assert(value != null,
-        failedAt(field, "Field $field doesn't have a constant initial value."));
-    return value;
-  }
-
-  void forEachParameter(covariant IndexedFunction function,
-      void f(DartType type, String name, ConstantValue defaultValue)) {
-    FunctionData data = _memberData[function.memberIndex];
-    data.forEachParameter(this, f);
-  }
-}
-
-/// Element builder used for creating elements and types corresponding to Kernel
-/// IR nodes.
-// TODO(johnniwinther): Use this in the JsStrategy
-class KernelToElementMapForBuildingImpl extends KernelToElementMapBase
-    with
-        KernelToElementMapForBuildingMixin,
-        KernelToElementMapForBuildingFromBaseMixin,
-        ElementCreatorMixin,
-        KElementCreatorMixin
-    implements KernelToWorldBuilder {
-  KernelToElementMapForBuildingImpl(
-      DiagnosticReporter reporter, Environment environment)
-      : super(reporter, environment);
-
-  @override
-  bool checkFamily(Entity entity) {
-    assert(
-        '$entity'.startsWith(kElementPrefix),
-        failedAt(entity,
-            "Unexpected entity $entity, expected family $kElementPrefix."));
-    return true;
-  }
-
-  ConstantEnvironment get constantEnvironment => _constantEnvironment;
-
-  ir.Library getKernelLibrary(KLibrary entity) =>
-      _libraryEnvs[entity.libraryIndex].library;
-
-  ir.Class getKernelClass(KClass entity) => _classEnvs[entity.classIndex].cls;
-
-  @override
-  Spannable getSpannable(MemberEntity member, ir.Node node) {
-    return _getSpannable(member, node);
-  }
-
-  @override
-  ir.Member getMemberNode(MemberEntity member) {
-    return _getMemberNode(member);
-  }
-
-  @override
-  ir.Class getClassNode(ClassEntity cls) {
-    return _getClassNode(cls);
-  }
-}
-
-/// [KernelToElementMap] implementation used for both world impact computation
-/// and SSA building.
-// TODO(johnniwinther): Remove this when [JsStrategy] is the default.
-class KernelToElementMapImpl extends KernelToElementMapForBuildingImpl
-    with
-        KernelToElementMapForImpactMixin,
-        KernelToElementMapForImpactImpl,
-        ElementCreatorMixin,
-        KElementCreatorMixin
-    implements KernelToElementMapForImpactImpl2 {
-  KernelToElementMapImpl(DiagnosticReporter reporter, Environment environment)
-      : super(reporter, environment);
-}
-
 class KernelElementEnvironment implements ElementEnvironment {
   final KernelToElementMapBase elementMap;
 
@@ -1781,7 +1677,6 @@ class JsToFrontendMapImpl extends JsToFrontendMapBase
 class JsKernelToElementMap extends KernelToElementMapBase
     with
         KernelToElementMapForBuildingMixin,
-        KernelToElementMapForBuildingFromBaseMixin,
         JsElementCreatorMixin,
         // TODO(johnniwinther): Avoid mixin in [ElementCreatorMixin]. The
         // codegen world should be a strict subset of the resolution world and
@@ -1931,4 +1826,30 @@ class JsKernelToElementMap extends KernelToElementMapBase
   ir.Class getClassNode(ClassEntity cls) {
     return _getClassNode(cls);
   }
+
+  @override
+  ConstantValue getFieldConstantValue(ir.Field field) {
+    // TODO(johnniwinther): Cache the result in [FieldData].
+    return getConstantValue(field.initializer,
+        requireConstant: field.isConst, implicitNull: !field.isConst);
+  }
+
+  bool hasConstantFieldInitializer(covariant IndexedField field) {
+    FieldData data = _memberData[field.memberIndex];
+    return getFieldConstantValue(data.node) != null;
+  }
+
+  ConstantValue getConstantFieldInitializer(covariant IndexedField field) {
+    FieldData data = _memberData[field.memberIndex];
+    ConstantValue value = getFieldConstantValue(data.node);
+    assert(value != null,
+        failedAt(field, "Field $field doesn't have a constant initial value."));
+    return value;
+  }
+
+  void forEachParameter(covariant IndexedFunction function,
+      void f(DartType type, String name, ConstantValue defaultValue)) {
+    FunctionData data = _memberData[function.memberIndex];
+    data.forEachParameter(this, f);
+  }
 }