[Android] Fix findbugs errors.

These were failing on Android Builder (dbg) FYI bot.

BUG=409152
TBR=qinmin@chromium.org

Review URL: https://codereview.chromium.org/522943003

Cr-Commit-Position: refs/heads/master@{#293206}

android_webview/java/src/org/chromium/android_webview/AwBrowserContext.java

@@ -56,7 +56,7 @@ public class AwBrowserContext {
 
     public HttpAuthDatabase getHttpAuthDatabase(Context context) {
         if (mHttpAuthDatabase == null) {
-            mHttpAuthDatabase = new HttpAuthDatabase(context, HTTP_AUTH_DATABASE_FILE);
+            mHttpAuthDatabase = HttpAuthDatabase.newInstance(context, HTTP_AUTH_DATABASE_FILE);
         }
         return mHttpAuthDatabase;
     }

android_webview/java/src/org/chromium/android_webview/HttpAuthDatabase.java

@@ -55,21 +55,26 @@ public class HttpAuthDatabase {
     private final Object mInitializedLock = new Object();
 
     /**
-     * Create an instance of HttpAuthDatabase for the named file, and kick-off background
-     * initialization of that database.
+     * Creates and returns an instance of HttpAuthDatabase for the named file, and kicks-off
+     * background initialization of that database.
      *
      * @param context the Context to use for opening the database
      * @param databaseFile Name of the file to be initialized.
      */
-    public HttpAuthDatabase(final Context context, final String databaseFile) {
+    public static HttpAuthDatabase newInstance(final Context context, final String databaseFile) {
+        final HttpAuthDatabase httpAuthDatabase = new HttpAuthDatabase();
         new Thread() {
             @Override
             public void run() {
-                initOnBackgroundThread(context, databaseFile);
+                httpAuthDatabase.initOnBackgroundThread(context, databaseFile);
             }
         }.start();
+        return httpAuthDatabase;
     }
 
+    // Prevent instantiation. Callers should use newInstance().
+    private HttpAuthDatabase() {}
+
     /**
      * Initializes the databases and notifies any callers waiting on waitForInit.
      *

android_webview/javatests/src/org/chromium/android_webview/test/HttpAuthDatabaseTest.java

@@ -32,7 +32,7 @@ public class HttpAuthDatabaseTest extends AndroidTestCase {
     @SmallTest
     @Feature({"AndroidWebView"})
     public void testAccessHttpAuthUsernamePassword() throws Exception {
-        HttpAuthDatabase instance = new HttpAuthDatabase(getContext(), TEST_DATABASE);
+        HttpAuthDatabase instance = HttpAuthDatabase.newInstance(getContext(), TEST_DATABASE);
 
         String host = "http://localhost:8080";
         String realm = "testrealm";

content/public/android/java/src/org/chromium/content/browser/crypto/CipherFactory.java

@@ -8,6 +8,7 @@ import android.os.AsyncTask;
 import android.os.Bundle;
 import android.util.Log;
 
+import java.io.IOException;
 import java.security.GeneralSecurityException;
 import java.security.Key;
 import java.security.SecureRandom;
@@ -153,7 +154,10 @@ public class CipherFactory {
                 try {
                     seed = mRandomNumberProvider.getBytes(NUM_BYTES);
                     iv = mRandomNumberProvider.getBytes(NUM_BYTES);
-                } catch (Exception e) {
+                } catch (IOException e) {
+                    Log.e(TAG, "Couldn't get generator data.");
+                    return null;
+                } catch (GeneralSecurityException e) {
                     Log.e(TAG, "Couldn't get generator data.");
                     return null;
                 }

content/shell/android/java/src/org/chromium/content_shell/Shell.java

@@ -194,7 +194,7 @@ public class Shell extends LinearLayout {
      * @return The sanitized URL.
      */
     public static String sanitizeUrl(String url) {
-        if (url == null) return url;
+        if (url == null) return null;
         if (url.startsWith("www.") || url.indexOf(":") == -1) url = "http://" + url;
         return url;
     }

media/base/android/java/src/org/chromium/media/MediaDrmBridge.java

@@ -205,7 +205,6 @@ public class MediaDrmBridge {
             if (MediaCrypto.isCryptoSchemeSupported(mSchemeUUID)) {
                 final byte[] mediaCryptoSession = mMediaCryptoSession.array();
                 mMediaCrypto = new MediaCrypto(mSchemeUUID, mediaCryptoSession);
-                assert mMediaCrypto != null;
                 Log.d(TAG, "MediaCrypto successfully created!");
                 mSessionIds.put(mMediaCryptoSession, INVALID_SESSION_ID);
                 // Notify the native code that MediaCrypto is ready.

net/android/java/src/org/chromium/net/NetStringUtil.java

@@ -23,15 +23,15 @@ public class NetStringUtil {
      * Attempts to convert text in a given character set to a Unicode string.
      * Returns null on failure.
      * @param text ByteBuffer containing the character array to convert.
-     * @param charset Character set it's in encoded in.
+     * @param charsetName Character set it's in encoded in.
      * @return: Unicode string on success, null on failure.
      */
     @CalledByNative
     private static String convertToUnicode(
             ByteBuffer text,
-            String charset_name) {
+            String charsetName) {
         try {
-            Charset charset = Charset.forName(charset_name);
+            Charset charset = Charset.forName(charsetName);
             CharsetDecoder decoder = charset.newDecoder();
             // On invalid characters, this will throw an exception.
             return decoder.decode(text).toString();
@@ -44,16 +44,15 @@ public class NetStringUtil {
      * Attempts to convert text in a given character set to a Unicode string,
      * and normalize it.  Returns null on failure.
      * @param text ByteBuffer containing the character array to convert.
-     * @param charset Character set it's in encoded in.
+     * @param charsetName Character set it's in encoded in.
      * @return: Unicode string on success, null on failure.
      */
     @CalledByNative
     private static String convertToUnicodeAndNormalize(
             ByteBuffer text,
-            String charset_name) {
-        String unicodeString = convertToUnicode(text, charset_name);
-        if (unicodeString == null)
-            return unicodeString;
+            String charsetName) {
+        String unicodeString = convertToUnicode(text, charsetName);
+        if (unicodeString == null) return null;
         return Normalizer.normalize(unicodeString, Normalizer.Form.NFC);
     }
 
@@ -62,15 +61,15 @@ public class NetStringUtil {
      * characters are replaced with U+FFFD.  Returns null if the character set
      * is not recognized.
      * @param text ByteBuffer containing the character array to convert.
-     * @param charset Character set it's in encoded in.
+     * @param charsetName Character set it's in encoded in.
      * @return: Unicode string on success, null on failure.
      */
     @CalledByNative
     private static String convertToUnicodeWithSubstitutions(
             ByteBuffer text,
-            String charset_name) {
+            String charsetName) {
         try {
-            Charset charset = Charset.forName(charset_name);
+            Charset charset = Charset.forName(charsetName);
 
             // TODO(mmenke):  Investigate if Charset.decode() can be used
             // instead.  The question is whether it uses the proper replace