Delete SINGLE_TARGET case as unused (#7442)

Bug: n/a
Test: n/a
Change-Id: Ia098cf97e93da64a93e7a812cc4f651e05802fb9

AOSP: f56b821d8cb7e18e8241dfa6692433996b744c06

Co-authored-by: Googler <[email protected]>

Author: sellophane

base/src/com/google/idea/blaze/base/qsync/DependencyTracker.java

@@ -20,10 +20,7 @@
 import com.google.idea.blaze.common.Label;
 import com.google.idea.blaze.exception.BuildException;
 import java.io.IOException;
-import java.nio.file.Path;
-import java.util.Optional;
 import java.util.Set;
-import javax.annotation.Nullable;
 
 /**
  * A service that tracks what files in the project can be analyzed and what is the status of their
@@ -41,8 +38,6 @@ boolean buildDependenciesForTargets(BlazeContext context, DependencyBuildRequest
   /** Request to {@link #buildDependenciesForTargets(BlazeContext, DependencyBuildRequest)}. */
   class DependencyBuildRequest {
     enum RequestType {
-      /** Build a single target and do not check if its dependencies were built. */
-      SINGLE_TARGET,
       /**
        * Build multiple targets and mark all dependencies as built even if they produce no
        * artifacts.
@@ -63,10 +58,6 @@ private DependencyBuildRequest(RequestType type, ImmutableSet<Label> targets) {
       this.targets = targets;
     }
 
-    public static DependencyBuildRequest singleTarget(Label target) {
-      return new DependencyBuildRequest(RequestType.SINGLE_TARGET, ImmutableSet.of(target));
-    }
-
     public static DependencyBuildRequest multiTarget(Set<Label> targets) {
       return new DependencyBuildRequest(RequestType.MULTIPLE_TARGETS, ImmutableSet.copyOf(targets));
     }

base/src/com/google/idea/blaze/base/qsync/DependencyTrackerImpl.java

@@ -91,8 +91,6 @@ private Optional<RequestedTargets> getRequestedTargets(
     switch (request.requestType) {
       case MULTIPLE_TARGETS:
         return snapshot.graph().computeRequestedTargets(request.targets);
-      case SINGLE_TARGET:
-        return Optional.of(new RequestedTargets(request.targets, request.targets));
       case WHOLE_PROJECT:
         return Optional.of(
             new RequestedTargets(