Browser: change default textencoding to GBK for chinese carrier

Some website don't set the text encoding,
so browser can't use the correct encoding to display it.

CRs-Fixed: 521106

Change-Id: I4a89492fdfec74da5599b97a169c53fa12f0537d
diff --git a/src/com/android/browser/BrowserSettings.java b/src/com/android/browser/BrowserSettings.java
index 9e0971d..17e2001 100644
--- a/src/com/android/browser/BrowserSettings.java
+++ b/src/com/android/browser/BrowserSettings.java
@@ -302,6 +302,13 @@
                 sFactoryResetUrl = mContext.getResources().getString(R.string.homepage_base);
             }
 
+            if (!mPrefs.contains(PREF_DEFAULT_TEXT_ENCODING)) {
+                if (!"default".equals(browserRes)) {
+                    mPrefs.edit().putString(PREF_DEFAULT_TEXT_ENCODING,
+                            "GBK").apply();
+                }
+            }
+
             if (sFactoryResetUrl.indexOf("{CID}") != -1) {
                 sFactoryResetUrl = sFactoryResetUrl.replace("{CID}",
                     BrowserProvider.getClientId(mContext.getContentResolver()));