Benchmark: Add JNI test for Decoder and Encoder

Test: adb shell am instrument -w -r  -e debug false -e class \
      'com.android.media.benchmark.tests.EncoderTest#testNativeEncoder' \
      com.android.media.benchmark/androidx.test.runner.AndroidJUnitRunner

Test: adb shell am instrument -w -r  -e debug false -e class\
      'com.android.media.benchmark.tests.DecoderTest#testNativeDecoder' \
      com.android.media.benchmark/androidx.test.runner.AndroidJUnitRunner

Bug: 140051680

Change-Id: I60582652e2e8b488ef87962add59ccd84fbb0094
diff --git a/media/tests/benchmark/MediaBenchmarkTest/build.gradle b/media/tests/benchmark/MediaBenchmarkTest/build.gradle
index b0ee692..b2aee1a 100644
--- a/media/tests/benchmark/MediaBenchmarkTest/build.gradle
+++ b/media/tests/benchmark/MediaBenchmarkTest/build.gradle
@@ -30,7 +30,7 @@
     compileSdkVersion 29
     defaultConfig {
         applicationId "com.android.media.benchmark"
-        minSdkVersion 21
+        minSdkVersion 28
         targetSdkVersion 29
         versionCode 1
         versionName "1.0"
@@ -48,6 +48,18 @@
             manifest.srcFile 'AndroidManifest.xml'
         }
     }
+    buildTypes {
+        release {
+            minifyEnabled false
+            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
+        }
+    }
+    externalNativeBuild {
+        cmake {
+            path "src/main/cpp/CMakeLists.txt"
+            version "3.10.2"
+        }
+    }
 }
 
 repositories {