Inform SkyframeExecutor of top level host configuration changes.

PiperOrigin-RevId: 242272628
diff --git a/src/main/java/com/google/devtools/build/lib/skyframe/SkyframeBuildView.java b/src/main/java/com/google/devtools/build/lib/skyframe/SkyframeBuildView.java
index 9e8ea6d..3cf640c 100644
--- a/src/main/java/com/google/devtools/build/lib/skyframe/SkyframeBuildView.java
+++ b/src/main/java/com/google/devtools/build/lib/skyframe/SkyframeBuildView.java
@@ -328,6 +328,7 @@
     }
     hostConfigurationCache.clear();
     this.topLevelHostConfiguration = topLevelHostConfiguration;
+    skyframeExecutor.updateTopLevelHostConfiguration(topLevelHostConfiguration);
   }
 
   /**
diff --git a/src/main/java/com/google/devtools/build/lib/skyframe/SkyframeExecutor.java b/src/main/java/com/google/devtools/build/lib/skyframe/SkyframeExecutor.java
index f614812..22ec4fa 100644
--- a/src/main/java/com/google/devtools/build/lib/skyframe/SkyframeExecutor.java
+++ b/src/main/java/com/google/devtools/build/lib/skyframe/SkyframeExecutor.java
@@ -1397,6 +1397,9 @@
     PrecomputedValue.REMOTE_OUTPUTS_MODE.set(injectable(), remoteOutputsMode);
   }
 
+  /** Called each time there is a new top-level host configuration. */
+  protected void updateTopLevelHostConfiguration(BuildConfiguration topLevelHostConfiguration) {}
+
   /**
    * Asks the Skyframe evaluator to build the value for BuildConfigurationCollection and returns the
    * result.