Remove unused import and resolve ReturnValueIgnored violation

Change-Id: Ib76a2d3c97d8d3b7f23d71de9b83c10257a187cb
diff --git a/src/main/java/com/android/tools/r8/profile/art/ArtProfile.java b/src/main/java/com/android/tools/r8/profile/art/ArtProfile.java
index ec7fecb..de8abb8 100644
--- a/src/main/java/com/android/tools/r8/profile/art/ArtProfile.java
+++ b/src/main/java/com/android/tools/r8/profile/art/ArtProfile.java
@@ -37,7 +37,7 @@
 
   public ArtProfile rewrittenWithLens(GraphLens lens) {
     return transform(
-        (classRule, builderFactory) -> builderFactory.apply(lens.lookupType(classRule.getType())),
+        (classRule, builderFactory) -> builderFactory.accept(lens.lookupType(classRule.getType())),
         (methodRule, builderFactory) ->
             builderFactory
                 .apply(lens.getRenamedMethodSignature(methodRule.getMethod()))
@@ -50,7 +50,7 @@
     assert !lens.isIdentityLens();
     return transform(
         (classRule, builderFactory) ->
-            builderFactory.apply(lens.lookupType(classRule.getType(), dexItemFactory)),
+            builderFactory.accept(lens.lookupType(classRule.getType(), dexItemFactory)),
         (methodRule, builderFactory) ->
             builderFactory
                 .apply(lens.lookupMethod(methodRule.getMethod(), dexItemFactory))
@@ -63,7 +63,7 @@
     return transform(
         (classRule, builderFactory) -> {
           if (!prunedItems.isRemoved(classRule.getType())) {
-            builderFactory.apply(classRule.getType());
+            builderFactory.accept(classRule.getType());
           }
         },
         (methodRule, builderFactory) -> {
@@ -78,8 +78,7 @@
   }
 
   private ArtProfile transform(
-      BiConsumer<ArtProfileClassRule, Function<DexType, ArtProfileClassRule.Builder>>
-          classTransformation,
+      BiConsumer<ArtProfileClassRule, Consumer<DexType>> classTransformation,
       BiConsumer<ArtProfileMethodRule, Function<DexMethod, ArtProfileMethodRule.Builder>>
           methodTransformation) {
     Map<DexReference, ArtProfileRule.Builder> ruleBuilders = new LinkedHashMap<>();
diff --git a/src/main/java/com/android/tools/r8/tracereferences/Tracer.java b/src/main/java/com/android/tools/r8/tracereferences/Tracer.java
index 1996e44..97c4499 100644
--- a/src/main/java/com/android/tools/r8/tracereferences/Tracer.java
+++ b/src/main/java/com/android/tools/r8/tracereferences/Tracer.java
@@ -37,7 +37,6 @@
 import com.android.tools.r8.graph.ProgramMethod;
 import com.android.tools.r8.graph.UseRegistry;
 import com.android.tools.r8.ir.desugar.LambdaDescriptor;
-import com.android.tools.r8.profile.art.ArtProfileCollection;
 import com.android.tools.r8.references.ClassReference;
 import com.android.tools.r8.references.FieldReference;
 import com.android.tools.r8.references.MethodReference;