Cleanup: Consolidate initialization of Android's SecureRandom class.

chrome/android/java/src/org/chromium/chrome/browser/WebappAuthenticator.java

Index: chrome/android/java/src/org/chromium/chrome/browser/WebappAuthenticator.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/WebappAuthenticator.java b/chrome/android/java/src/org/chromium/chrome/browser/WebappAuthenticator.java
index f71fa671af9a248a3922d71804a68bebeea65b90..26ce9a33ea8cbeeac8ade29faca8d97b77e9c6fa 100644
--- a/chrome/android/java/src/org/chromium/chrome/browser/WebappAuthenticator.java
+++ b/chrome/android/java/src/org/chromium/chrome/browser/WebappAuthenticator.java
@@ -8,6 +8,8 @@ import android.content.Context;
 import android.os.AsyncTask;
 import android.util.Log;
 
+import org.chromium.base.SecureRandomInitializer;
+
 import java.io.File;
 import java.io.FileInputStream;
 import java.io.FileOutputStream;
@@ -191,20 +193,7 @@ public class WebappAuthenticator {
                 public SecretKey call() throws Exception {
                     KeyGenerator generator = KeyGenerator.getInstance(MAC_ALGORITHM_NAME);
                     SecureRandom random = SecureRandom.getInstance("SHA1PRNG");
-
-                    // Versions of SecureRandom from Android <= 4.3 do not seed themselves as
-                    // securely as possible. This workaround should suffice until the fixed version
-                    // is deployed to all users. getRandomBytes, which reads from /dev/urandom,
-                    // which is as good as the platform can get.
-                    //
-                    // TODO(palmer): Consider getting rid of this once the updated platform has
-                    // shipped to everyone. Alternately, leave this in as a defense against other
-                    // bugs in SecureRandom.
-                    byte[] seed = getRandomBytes(MAC_KEY_BYTE_COUNT);
-                    if (seed == null) {
-                        return null;
-                    }
-                    random.setSeed(seed);
+                    SecureRandomInitializer.initialize(random);
                     generator.init(MAC_KEY_BYTE_COUNT * 8, random);
                     return generator.generateKey();
                 }
@@ -213,29 +202,6 @@ public class WebappAuthenticator {
         }
     }
 
-    private static byte[] getRandomBytes(int count) {
-        FileInputStream fis = null;
-        try {
-            fis = new FileInputStream("/dev/urandom");
-            byte[] bytes = new byte[count];
-            if (bytes.length != fis.read(bytes)) {
-                return null;
-            }
-            return bytes;
-        } catch (Throwable t) {
-            // This causes the ultimate caller, i.e. getMac, to fail.
-            return null;
-        } finally {
-            try {
-                if (fis != null) {
-                    fis.close();
-                }
-            } catch (IOException e) {
-                // Nothing we can do.
-            }
-        }
-    }
-
     /**
      * @return A Mac, or null if it is not possible to instantiate one.
      */