Changes after review

- Replace leaking ModuleResolverTracker with use of ModuleDescriptor.Capabilies
- Provide API for retrieving ResolverForProject from ResolutionFacade
- Update names

core/descriptors/src/org/jetbrains/kotlin/descriptors/ModuleDescriptor.kt

@@ -20,7 +20,6 @@ import org.jetbrains.kotlin.builtins.KotlinBuiltIns
 import org.jetbrains.kotlin.name.FqName
 import org.jetbrains.kotlin.name.Name
 import org.jetbrains.kotlin.platform.TargetPlatform
-import org.jetbrains.kotlin.resolve.AnchorProvider
 
 interface ModuleDescriptor : DeclarationDescriptor {
     override fun getContainingDeclaration(): DeclarationDescriptor? = null
@@ -62,6 +61,4 @@ interface ModuleDescriptor : DeclarationDescriptor {
     val isValid: Boolean
 
     fun assertValid()
-
-    val anchorProvider: AnchorProvider
 }

core/descriptors/src/org/jetbrains/kotlin/descriptors/findClassInModule.kt

@@ -18,6 +18,7 @@ package org.jetbrains.kotlin.descriptors
 
 import org.jetbrains.kotlin.incremental.components.NoLookupLocation
 import org.jetbrains.kotlin.name.ClassId
+import org.jetbrains.kotlin.resolve.RESOLUTION_ANCHOR_PROVIDER_CAPABILITY
 
 fun ModuleDescriptor.findClassifierAcrossModuleDependencies(classId: ClassId): ClassifierDescriptor? = withAnchorFallback {
     val packageViewDescriptor = getPackage(classId.packageFqName)
@@ -39,7 +40,7 @@ fun ModuleDescriptor.findClassifierAcrossModuleDependencies(classId: ClassId): C
 private inline fun ModuleDescriptor.withAnchorFallback(
     crossinline doSearch: ModuleDescriptor.() -> ClassifierDescriptor? 
 ): ClassifierDescriptor? {
-    val anchor = anchorProvider.getAnchor(this)
+    val anchor = getCapability(RESOLUTION_ANCHOR_PROVIDER_CAPABILITY)?.getResolutionAnchor(this)
     return if (anchor == null) doSearch() else doSearch() ?: anchor.doSearch()
 }
 

core/descriptors/src/org/jetbrains/kotlin/descriptors/impl/ModuleDescriptorImpl.kt

@@ -25,7 +25,6 @@ import org.jetbrains.kotlin.descriptors.annotations.Annotations
 import org.jetbrains.kotlin.name.FqName
 import org.jetbrains.kotlin.name.Name
 import org.jetbrains.kotlin.platform.TargetPlatform
-import org.jetbrains.kotlin.resolve.AnchorProvider
 import org.jetbrains.kotlin.storage.StorageManager
 import org.jetbrains.kotlin.types.checker.REFINER_CAPABILITY
 import org.jetbrains.kotlin.types.checker.Ref
@@ -40,7 +39,6 @@ class ModuleDescriptorImpl @JvmOverloads constructor(
     override val platform: TargetPlatform? = null,
     capabilities: Map<ModuleDescriptor.Capability<*>, Any?> = emptyMap(),
     override val stableName: Name? = null,
-    override val anchorProvider: AnchorProvider = AnchorProvider.Default,
 ) : DeclarationDescriptorImpl(Annotations.EMPTY, moduleName), ModuleDescriptor {
     private val capabilities: Map<ModuleDescriptor.Capability<*>, Any?>
 

core/descriptors/src/org/jetbrains/kotlin/resolve/AnchorProvider.kt

@@ -1,14 +0,0 @@
-/*
- * Copyright 2010-2020 JetBrains s.r.o. and Kotlin Programming Language contributors.
- * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
- */
-
-package org.jetbrains.kotlin.resolve
-
-import org.jetbrains.kotlin.descriptors.ModuleDescriptor
-
-abstract class AnchorProvider {
-    open fun getAnchor(moduleDescriptor: ModuleDescriptor): ModuleDescriptor? = null
-    
-    companion object Default : AnchorProvider()
-}

core/descriptors/src/org/jetbrains/kotlin/resolve/ResolutionAnchorProvider.kt

@@ -0,0 +1,20 @@
+/*
+ * Copyright 2010-2020 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
+ */
+
+package org.jetbrains.kotlin.resolve
+
+import org.jetbrains.kotlin.descriptors.ModuleDescriptor
+
+interface ResolutionAnchorProvider {
+    fun getResolutionAnchor(moduleDescriptor: ModuleDescriptor): ModuleDescriptor? = null
+
+    companion object {
+        val Default: ResolutionAnchorProvider = object : ResolutionAnchorProvider {
+            override fun getResolutionAnchor(moduleDescriptor: ModuleDescriptor): ModuleDescriptor? = null
+        }
+    }
+}
+
+val RESOLUTION_ANCHOR_PROVIDER_CAPABILITY = ModuleDescriptor.Capability<ResolutionAnchorProvider>("ResolutionAnchorProvider")

core/descriptors/src/org/jetbrains/kotlin/types/ErrorUtils.java

@@ -31,7 +31,6 @@ import org.jetbrains.kotlin.incremental.components.LookupLocation;
 import org.jetbrains.kotlin.name.FqName;
 import org.jetbrains.kotlin.name.Name;
 import org.jetbrains.kotlin.platform.TargetPlatform;
-import org.jetbrains.kotlin.resolve.AnchorProvider;
 import org.jetbrains.kotlin.resolve.descriptorUtil.DescriptorUtilsKt;
 import org.jetbrains.kotlin.resolve.scopes.DescriptorKindFilter;
 import org.jetbrains.kotlin.resolve.scopes.MemberScope;
@@ -54,12 +53,6 @@ public class ErrorUtils {
 
     static {
         ERROR_MODULE = new ModuleDescriptor() {
-            @NotNull
-            @Override
-            public AnchorProvider getAnchorProvider() {
-                return AnchorProvider.Default;
-            }
-
             @Nullable
             @Override
             public <T> T getCapability(@NotNull Capability<T> capability) {