Reland of Move language pak files to assets.

base/android/java/src/org/chromium/base/ResourceExtractor.java

Index: base/android/java/src/org/chromium/base/ResourceExtractor.java
diff --git a/base/android/java/src/org/chromium/base/ResourceExtractor.java b/base/android/java/src/org/chromium/base/ResourceExtractor.java
index 26db654f5a781154e68de96973942f9edd6ea9ab..e8bbc19f7fe5699cdc53f7982708b0bb9e5890d7 100644
--- a/base/android/java/src/org/chromium/base/ResourceExtractor.java
+++ b/base/android/java/src/org/chromium/base/ResourceExtractor.java
@@ -4,7 +4,6 @@
 
 package org.chromium.base;
 
-import android.content.Context;
 import android.content.SharedPreferences;
 import android.content.pm.PackageInfo;
 import android.content.pm.PackageManager;
@@ -12,8 +11,6 @@ import android.os.AsyncTask;
 import android.os.Handler;
 import android.os.Looper;
 
-import org.chromium.base.annotations.SuppressFBWarnings;
-
 import java.io.File;
 import java.io.FileOutputStream;
 import java.io.IOException;
@@ -21,6 +18,7 @@ import java.io.InputStream;
 import java.io.OutputStream;
 import java.util.ArrayList;
 import java.util.List;
+import java.util.Locale;
 import java.util.concurrent.CancellationException;
 import java.util.concurrent.ExecutionException;
 
@@ -35,23 +33,7 @@ public class ResourceExtractor {
     private static final String V8_NATIVES_DATA_FILENAME = "natives_blob.bin";
     private static final String V8_SNAPSHOT_DATA_FILENAME = "snapshot_blob.bin";
     private static final String APP_VERSION_PREF = "org.chromium.base.ResourceExtractor.Version";
-
-    private static ResourceEntry[] sResourcesToExtract = new ResourceEntry[0];
-
-    /**
-     * Holds information about a res/raw file (e.g. locale .pak files).
-     */
-    public static final class ResourceEntry {
-        public final int resourceId;
-        public final String pathWithinApk;
-        public final String extractedFileName;
-
-        public ResourceEntry(int resourceId, String pathWithinApk, String extractedFileName) {
-            this.resourceId = resourceId;
-            this.pathWithinApk = pathWithinApk;
-            this.extractedFileName = extractedFileName;
-        }
-    }
+    private static final String FALLBACK_LOCALE = "en-US";
 
     private class ExtractTask extends AsyncTask<Void, Void, Void> {
         private static final int BUFFER_SIZE = 16 * 1024;
@@ -107,16 +89,16 @@ public class ResourceExtractor {
             TraceEvent.begin("WalkAssets");
             byte[] buffer = new byte[BUFFER_SIZE];
             try {
-                for (ResourceEntry entry : sResourcesToExtract) {
-                    File output = new File(outputDir, entry.extractedFileName);
+                for (String assetName : mAssetsToExtract) {
+                    File output = new File(outputDir, assetName);
                     // TODO(agrieve): It would be better to check that .length == expectedLength.
                     //     http://crbug.com/606413
                     if (output.length() != 0) {
                         continue;
                     }
                     TraceEvent.begin("ExtractResource");
-                    InputStream inputStream = mContext.getResources().openRawResource(
-                            entry.resourceId);
+                    InputStream inputStream =
+                            ContextUtils.getApplicationContext().getAssets().open(assetName);
                     try {
                         extractResourceHelper(inputStream, output, buffer);
                     } finally {
@@ -128,7 +110,7 @@ public class ResourceExtractor {
                 // Try to recover here, can we try again after deleting files instead of
                 // returning null? It might be useful to gather UMA here too to track if
                 // this happens with regularity.
-                Log.w(TAG, "Exception unpacking required pak resources: %s", e.getMessage());
+                Log.w(TAG, "Exception unpacking required pak asset: %s", e.getMessage());
                 deleteFiles();
                 return;
             } finally {
@@ -166,10 +148,11 @@ public class ResourceExtractor {
 
         /** Returns a number that is different each time the apk changes. */
         private long getApkVersion() {
-            PackageManager pm = mContext.getPackageManager();
+            PackageManager pm = ContextUtils.getApplicationContext().getPackageManager();
             try {
                 // More appropriate would be versionCode, but it doesn't change while developing.
-                PackageInfo pi = pm.getPackageInfo(mContext.getPackageName(), 0);
+                PackageInfo pi =
+                        pm.getPackageInfo(ContextUtils.getApplicationContext().getPackageName(), 0);
                 return pi.lastUpdateTime;
             } catch (PackageManager.NameNotFoundException e) {
                 throw new RuntimeException(e);
@@ -177,31 +160,34 @@ public class ResourceExtractor {
         }
     }
 
-    private final Context mContext;
     private ExtractTask mExtractTask;
+    private String[] mAssetsToExtract;
 
     private static ResourceExtractor sInstance;
 
-    public static ResourceExtractor get(Context context) {
+    public static ResourceExtractor get() {
         if (sInstance == null) {
-            sInstance = new ResourceExtractor(context);
+            sInstance = new ResourceExtractor();
+            sInstance.mAssetsToExtract = detectFilesToExtract();

[nyquist, 2016/10/03 04:53:59]

Nit: Could you add a comment as to why is this initialized here instead of in
the constructor (because it could then be final)?

[agrieve, 2016/10/03 20:10:17]

Made it final.

         }
         return sInstance;
     }
 
-    /**
-     * Specifies the files that should be extracted from the APK.
-     * and moved to {@link #getOutputDir()}.
-     */
-    @SuppressFBWarnings("EI_EXPOSE_STATIC_REP2")
-    public static void setResourcesToExtract(ResourceEntry[] entries) {
-        assert (sInstance == null || sInstance.mExtractTask == null)
-                : "Must be called before startExtractingResources is called";
-        sResourcesToExtract = entries;
+    private static boolean isPakFileForLanguage(String pakFileName, String language) {
+        return pakFileName.startsWith(language)
+                && ".-".indexOf(pakFileName.charAt(language.length())) != -1;

[Ted C, 2016/09/30 17:03:15]

puts on the ol' paranoid hat, should we do pakFileName.length() >
language.length()?

And while this is more concise, I think something like this is clearer to read:

if (!pakFileName.startsWith(language) || pakFileName.length() <=
language.length()) {
    return false;
}
char c = pakFileName.charAt(language.length());
return c == '.' || c == '-';

Seems clearer to me, but I'll defer to you.

[nyquist, 2016/10/03 04:53:59]

I agree with Ted here. It's not as readable as it is right now.

[agrieve, 2016/10/03 20:10:17]

Done.

     }
 
-    private ResourceExtractor(Context context) {
-        mContext = context.getApplicationContext();
+    private static String[] detectFilesToExtract() {
+        String language = LocaleUtils.getLanguage(Locale.getDefault());
+        ArrayList<String> activeLocalePakFiles = new ArrayList<String>(5);

[nyquist, 2016/10/03 04:53:59]

Nit: Care to add a tiny comment in case future readers also want to know why you
used 5 as the initial size?

[agrieve, 2016/10/03 20:10:16]

Done.

+        for (String pakFileName : BuildConfig.COMPRESSED_ASSETS) {

[michaelbai, 2016/09/29 20:47:05]

Do we still have pak file compressed?

[agrieve, 2016/09/30 00:04:37]

For Chrome.apk, yes. Not for Monochrome nor webview. (see
//chrome/android:chrome_public_locale_pak_assets in this patch)

[michaelbai, 2016/09/30 00:10:39]

Oh, right, Chrome still uses compressed pak.

+            if (isPakFileForLanguage(pakFileName, language)
+                    || isPakFileForLanguage(pakFileName, FALLBACK_LOCALE)) {
+                activeLocalePakFiles.add(pakFileName);
+            }
+        }
+        return activeLocalePakFiles.toArray(new String[0]);

[nyquist, 2016/10/03 04:53:59]

Tiny nit: Since this happens early, and we already know it, could we just do new
String[activeLocalePakFiles.size()] here? Otherwise we create a throw-away
object, and some other unnecessary stuff. With a correctly sized array, I think
we can use System.arraycopy.

[agrieve, 2016/10/03 20:10:17]

Done.

     }
 
     /**
@@ -329,6 +315,6 @@ public class ResourceExtractor {
      * Pak extraction not necessarily required by the embedder.
      */
     private static boolean shouldSkipPakExtraction() {
-        return sResourcesToExtract.length == 0;
+        return get().mAssetsToExtract.length == 0;
     }
 }