Merge code which extracts assets from APK to file

chrome/android/webapk/shell_apk/javatests/dex_optimizer/src/org/chromium/webapk/shell_apk/test/dex_optimizer/DexOptimizerServiceImpl.java

Index: chrome/android/webapk/shell_apk/javatests/dex_optimizer/src/org/chromium/webapk/shell_apk/test/dex_optimizer/DexOptimizerServiceImpl.java
diff --git a/chrome/android/webapk/shell_apk/javatests/dex_optimizer/src/org/chromium/webapk/shell_apk/test/dex_optimizer/DexOptimizerServiceImpl.java b/chrome/android/webapk/shell_apk/javatests/dex_optimizer/src/org/chromium/webapk/shell_apk/test/dex_optimizer/DexOptimizerServiceImpl.java
index 05718d44a7b5f382daa7617f640f99511a5f00bf..4034361d9291c945ebddab55993ad9913025a42d 100644
--- a/chrome/android/webapk/shell_apk/javatests/dex_optimizer/src/org/chromium/webapk/shell_apk/test/dex_optimizer/DexOptimizerServiceImpl.java
+++ b/chrome/android/webapk/shell_apk/javatests/dex_optimizer/src/org/chromium/webapk/shell_apk/test/dex_optimizer/DexOptimizerServiceImpl.java
@@ -13,11 +13,10 @@ import org.chromium.base.FileUtils;
 import org.chromium.webapk.lib.client.DexOptimizer;
 
 import java.io.File;
-import java.io.FileOutputStream;
-import java.io.IOException;
-import java.io.InputStream;
-import java.io.OutputStream;
 
+/**
+ * Service which extracts a dex file from parent APK and optimizes it.
+ */
 public class DexOptimizerServiceImpl extends Service {
     private static int sCounter = 0;
 
@@ -46,7 +45,8 @@ public class DexOptimizerServiceImpl extends Service {
                 ++sCounter;
 
                 File dexFile = new File(getDir(DEX_DIR, Context.MODE_PRIVATE), dexName);
-                if (!extractAsset(DEX_ASSET_NAME, dexFile)) {
+                if (!FileUtils.extractAsset(
+                            DexOptimizerServiceImpl.this, DEX_ASSET_NAME, dexFile)) {
                     return null;
                 }
 
@@ -62,27 +62,6 @@ public class DexOptimizerServiceImpl extends Service {
                 }
                 return dexFile.getPath();
             }
-
-
-            /**
-             * Extracts an asset from the app's APK to a file.
-             * @param assetName Name of the asset to extract.
-             * @param dest File to extract the asset to.
-             * @return true on success.
-             */
-            public boolean extractAsset(String assetName, File dest) {
-                try (InputStream inputStream = getAssets().open(assetName);
-                    OutputStream outputStream = new FileOutputStream(dest)) {
-                    byte[] buffer = new byte[16 * 1024];
-                    int c;
-                    while ((c = inputStream.read(buffer, 0, buffer.length)) != -1) {
-                        outputStream.write(buffer, 0, c);
-                    }
-                } catch (IOException e) {
-                    return false;
-                }
-                return true;
-            }
         };
     }
 }