support lazy calculation of tooltip for breadcrumbs

json/src/com/intellij/json/breadcrumbs/JsonBreadcrumbsProvider.java

@@ -55,11 +55,6 @@ public class JsonBreadcrumbsProvider implements BreadcrumbsProvider {
     return JsonSchemaDocumentationProvider.findSchemaAndGenerateDoc(e, null, true);
   }
 
-  @Override
-  public boolean isDeferredTooltipEvaluation() {
-    return true;
-  }
-
   @NotNull
   @Override
   public List<? extends Action> getContextActions(@NotNull PsiElement element) {

platform/editor-ui-api/src/com/intellij/ui/breadcrumbs/BreadcrumbsProvider.java

@@ -55,13 +55,6 @@ public interface BreadcrumbsProvider {
     return null;
   }
 
-  /**
-   * @return should return true in case when tooltip evaluation is slow
-   */
-  default boolean isDeferredTooltipEvaluation() {
-    return false;
-  }
-
   /**
    * @param element that represents a single crumb
    * @return an element that represents a parent crumb, or {@code null}

platform/platform-api/src/com/intellij/ui/components/breadcrumbs/Crumb.java

@@ -39,7 +39,7 @@ public interface Crumb {
     public Impl(@NotNull BreadcrumbsProvider provider, @NotNull PsiElement element) {
       this(provider.getElementIcon(element),
            provider.getElementInfo(element),
-           provider.isDeferredTooltipEvaluation() ? null : provider.getElementTooltip(element),
+           provider.getElementTooltip(element),
            provider.getContextActions(element));
     }
 

xml/impl/src/com/intellij/xml/breadcrumbs/PsiCrumb.java

@@ -7,31 +7,29 @@ import com.intellij.ui.breadcrumbs.BreadcrumbsProvider;
 import com.intellij.ui.components.breadcrumbs.Crumb;
 import org.jetbrains.annotations.Nullable;
 
-import java.util.function.Function;
-
 /**
  * @author Sergey.Malenkov
  */
 final class PsiCrumb extends Crumb.Impl {
   private final PsiAnchor anchor;
-  private final Function<PsiElement, String> tooltipEvaluator;
+  private BreadcrumbsProvider provider;
+  private String tooltip;
   CrumbPresentation presentation;
 
   PsiCrumb(PsiElement element, BreadcrumbsProvider provider) {
-    super(provider, element);
+    super(provider.getElementIcon(element), provider.getElementInfo(element), null, provider.getContextActions(element));
     anchor = PsiAnchor.create(element);
-    tooltipEvaluator = provider.isDeferredTooltipEvaluation() ? e -> provider.getElementTooltip(e) : null;
+    this.provider = provider;
   }
 
   @Override
   public String getTooltip() {
-    if (tooltipEvaluator != null) {
+    if (tooltip == null && provider != null) {
       PsiElement element = getElement(this);
-      if (element != null) {
-        return tooltipEvaluator.apply(element);
-      }
+      if (element != null) tooltip = provider.getElementTooltip(element);
+      provider = null; // do not try recalculate tooltip
     }
-    return super.getTooltip();
+    return tooltip;
   }
 
   @Nullable