Add perf test for SystemFonts.getAvailableFonts

Bug: 188201287
Test: atest SystemFontsPerfTest
Change-Id: Id08a53e980a012a682e95e7b41d363aae31c1232

apct-tests/perftests/core/src/android/text/SystemFontsPerfTest.java

@@ -0,0 +1,49 @@
+/*
+ * Copyright (C) 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package android.text;
+
+import android.graphics.fonts.SystemFonts;
+import android.perftests.utils.BenchmarkState;
+import android.perftests.utils.PerfStatusReporter;
+
+import androidx.test.filters.LargeTest;
+import androidx.test.runner.AndroidJUnit4;
+
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+
+
+@LargeTest
+@RunWith(AndroidJUnit4.class)
+public class SystemFontsPerfTest {
+    @Rule
+    public PerfStatusReporter mPerfStatusReporter = new PerfStatusReporter();
+
+    @Test
+    public void getAvailableFonts() {
+        final BenchmarkState state = mPerfStatusReporter.getBenchmarkState();
+        while (state.keepRunning()) {
+            state.pauseTiming();
+            SystemFonts.resetAvailableFonts();
+            System.gc();
+            state.resumeTiming();
+
+            SystemFonts.getAvailableFonts();
+        }
+    }
+}

graphics/java/android/graphics/fonts/SystemFonts.java

@@ -85,6 +85,15 @@ public final class SystemFonts {
         }
     }
 
+    /**
+     * @hide
+     */
+    public static void resetAvailableFonts() {
+        synchronized (LOCK) {
+            sAvailableFonts = null;
+        }
+    }
+
     private static @Nullable ByteBuffer mmap(@NonNull String fullPath) {
         try (FileInputStream file = new FileInputStream(fullPath)) {
             final FileChannel fileChannel = file.getChannel();