diff --git a/src/main/java/com/android/tools/r8/shaking/ProguardConfiguration.java b/src/main/java/com/android/tools/r8/shaking/ProguardConfiguration.java
index 955069f..3eb32b9 100644
--- a/src/main/java/com/android/tools/r8/shaking/ProguardConfiguration.java
+++ b/src/main/java/com/android/tools/r8/shaking/ProguardConfiguration.java
@@ -10,6 +10,7 @@
 import com.android.tools.r8.position.Position;
 import com.android.tools.r8.utils.InternalOptions.PackageObfuscationMode;
 import com.android.tools.r8.utils.Reporter;
+import com.android.tools.r8.utils.StringUtils;
 import com.google.common.collect.ImmutableList;
 import com.google.common.collect.Sets;
 import java.nio.file.Path;
@@ -671,11 +672,11 @@
     StringBuilder builder = new StringBuilder();
     if (!keepAttributes.isEmpty()) {
       keepAttributes.append(builder);
-      builder.append('\n');
+      builder.append(StringUtils.LINE_SEPARATOR);
     }
     for (ProguardConfigurationRule rule : rules) {
       rule.append(builder);
-      builder.append('\n');
+      builder.append(StringUtils.LINE_SEPARATOR);
     }
     return builder.toString();
   }
diff --git a/src/test/java/com/android/tools/r8/shaking/LibraryProvidedProguardRulesR8SpecificTest.java b/src/test/java/com/android/tools/r8/shaking/LibraryProvidedProguardRulesR8SpecificTest.java
index aba5cfa..c3fd851 100644
--- a/src/test/java/com/android/tools/r8/shaking/LibraryProvidedProguardRulesR8SpecificTest.java
+++ b/src/test/java/com/android/tools/r8/shaking/LibraryProvidedProguardRulesR8SpecificTest.java
@@ -47,27 +47,27 @@
   }
 
   private static final String EXPECTED_A =
-      StringUtils.unixLines(
+      StringUtils.lines(
           "-keep class A1 {", "  <init>();", "}", "-keep class A2 {", "  <init>();", "}");
 
   private static final String EXPECTED_B =
-      StringUtils.unixLines(
+      StringUtils.lines(
           "-keep class B1 {", "  <init>();", "}", "-keep class B2 {", "  <init>();", "}");
 
   private static final String EXPECTED_C =
-      StringUtils.unixLines(
+      StringUtils.lines(
           "-keep class C1 {", "  <init>();", "}", "-keep class C2 {", "  <init>();", "}");
 
   private static final String EXPECTED_D =
-      StringUtils.unixLines(
+      StringUtils.lines(
           "-keep class D1 {", "  <init>();", "}", "-keep class D2 {", "  <init>();", "}");
 
   private static final String EXPECTED_E =
-      StringUtils.unixLines(
+      StringUtils.lines(
           "-keep class E1 {", "  <init>();", "}", "-keep class E2 {", "  <init>();", "}");
 
   private static final String EXPECTED_X =
-      StringUtils.unixLines(
+      StringUtils.lines(
           "-keep class X1 {", "  <init>();", "}", "-keep class X2 {", "  <init>();", "}");
 
   private Path buildLibrary() throws Exception {
@@ -152,22 +152,21 @@
   @Test
   public void runTestVersion3() throws Exception {
     runTest(
-        SemanticVersion.create(3, 0, 0),
-        StringUtils.unixLines(EXPECTED_A.trim(), EXPECTED_C.trim()));
+        SemanticVersion.create(3, 0, 0), StringUtils.lines(EXPECTED_A.trim(), EXPECTED_C.trim()));
   }
 
   @Test
   public void runTestVersion4() throws Exception {
     runTest(
         SemanticVersion.create(4, 0, 0),
-        StringUtils.unixLines(EXPECTED_A.trim(), EXPECTED_B.trim(), EXPECTED_C.trim()));
+        StringUtils.lines(EXPECTED_A.trim(), EXPECTED_B.trim(), EXPECTED_C.trim()));
   }
 
   @Test
   public void runTestVersion5() throws Exception {
     runTest(
         SemanticVersion.create(5, 0, 0),
-        StringUtils.unixLines(
+        StringUtils.lines(
             EXPECTED_A.trim(), EXPECTED_B.trim(), EXPECTED_C.trim(), EXPECTED_D.trim()));
   }
 
@@ -175,7 +174,7 @@
   public void runTestVersion8() throws Exception {
     runTest(
         SemanticVersion.create(8, 0, 0),
-        StringUtils.unixLines(
+        StringUtils.lines(
             EXPECTED_A.trim(), EXPECTED_B.trim(), EXPECTED_C.trim(), EXPECTED_D.trim()));
   }
 
@@ -183,28 +182,26 @@
   public void runTestVersion8_1() throws Exception {
     runTest(
         SemanticVersion.create(8, 1, 0),
-        StringUtils.unixLines(EXPECTED_A.trim(), EXPECTED_B.trim(), EXPECTED_C.trim()));
+        StringUtils.lines(EXPECTED_A.trim(), EXPECTED_B.trim(), EXPECTED_C.trim()));
   }
 
   @Test
   public void runTestVersion8_2() throws Exception {
     runTest(
-        SemanticVersion.create(8, 2, 0),
-        StringUtils.unixLines(EXPECTED_A.trim(), EXPECTED_B.trim()));
+        SemanticVersion.create(8, 2, 0), StringUtils.lines(EXPECTED_A.trim(), EXPECTED_B.trim()));
   }
 
   @Test
   public void runTestVersion10() throws Exception {
     runTest(
-        SemanticVersion.create(10, 0, 0),
-        StringUtils.unixLines(EXPECTED_A.trim(), EXPECTED_B.trim()));
+        SemanticVersion.create(10, 0, 0), StringUtils.lines(EXPECTED_A.trim(), EXPECTED_B.trim()));
   }
 
   @Test
   public void runTestVersion10_5() throws Exception {
     runTest(
         SemanticVersion.create(10, 5, 0),
-        StringUtils.unixLines(EXPECTED_A.trim(), EXPECTED_B.trim(), EXPECTED_E.trim()));
+        StringUtils.lines(EXPECTED_A.trim(), EXPECTED_B.trim(), EXPECTED_E.trim()));
   }
 
   @Test
@@ -235,7 +232,7 @@
         .inspectProguardConfiguration(
             configuration ->
                 assertEquals(
-                    StringUtils.unixLines(EXPECTED_A.trim(), EXPECTED_B.trim(), EXPECTED_C.trim()),
+                    StringUtils.lines(EXPECTED_A.trim(), EXPECTED_B.trim(), EXPECTED_C.trim()),
                     configuration.toString()));
   }