Implement HttpUserAgentSettings delegate for Android WebView

android_webview/java/src/org/chromium/android_webview/AwContents.java

Index: android_webview/java/src/org/chromium/android_webview/AwContents.java
diff --git a/android_webview/java/src/org/chromium/android_webview/AwContents.java b/android_webview/java/src/org/chromium/android_webview/AwContents.java
index f901384752a503e169e19b9568866328fe7d3293..1535ba741c22fdc8652ac6b3cd6d245158b800e2 100644
--- a/android_webview/java/src/org/chromium/android_webview/AwContents.java
+++ b/android_webview/java/src/org/chromium/android_webview/AwContents.java
@@ -45,6 +45,7 @@ import android.widget.OverScroller;
 import org.chromium.android_webview.permission.AwPermissionRequest;
 import org.chromium.base.CalledByNative;
 import org.chromium.base.JNINamespace;
+import org.chromium.base.LocaleUtils;
 import org.chromium.base.ThreadUtils;
 import org.chromium.base.TraceEvent;
 import org.chromium.base.VisibleForTesting;
@@ -295,6 +296,8 @@ public class AwContents implements SmartClipProvider,
     // Do not use directly, call isDestroyed() instead.
     private boolean mIsDestroyed = false;
 
+    private static String sCurrentLocale;
+
     private static final class DestroyRunnable implements Runnable {
         private final long mNativeAwContents;
 
@@ -609,7 +612,12 @@ public class AwContents implements SmartClipProvider,
         public void onLowMemory() {}
 
         @Override
-        public void onConfigurationChanged(Configuration configuration) {}
+        public void onConfigurationChanged(Configuration configuration) {

[Torne, 2015/07/17 13:33:19]

Hm, so there's a bit of a problem here potentially: we only have our component
callbacks registered during the time when we are attached to a view hierarchy.
This means that we will miss locale changes that occur while the webview is
detached, and we'll never notice locale changes at all for apps which don't
attach the webview (some apps use it just to draw in an "offscreen" mode).

We wouldn't want to call through all these layers up to java for every network
request either, though. We might have to accept the latter as a limitation, but
perhaps we should recheck the locale when reattached to the view hierarchy? I'm
not sure if this will ever matter in practise but it seems possible that the
embedding activity might detach the webview on config change (so it can keep the
webview alive while recreating its layouts) - I'm not 100% sure that this method
will be called in that case, the order of operations is non-obvious..

[ctserng, 2015/07/17 16:51:15]

Good point.  I'll see if it's possible to handle the reattach case.

+            String newLocale = LocaleUtils.getLocale(configuration.locale);
+            if (!sCurrentLocale.equals(newLocale)) {
+                sCurrentLocale = newLocale;
+            }
+        }
     };
 
     //--------------------------------------------------------------------------------------------
@@ -651,6 +659,8 @@ public class AwContents implements SmartClipProvider,
             InternalAccessDelegate internalAccessAdapter, NativeGLDelegate nativeGLDelegate,
             AwContentsClient contentsClient, AwSettings settings,
             DependencyFactory dependencyFactory) {
+        sCurrentLocale = LocaleUtils.getDefaultLocale();
+
         mBrowserContext = browserContext;
 
         // setWillNotDraw(false) is required since WebView draws it's own contents using it's
@@ -2392,6 +2402,11 @@ public class AwContents implements SmartClipProvider,
     }
 
     @CalledByNative
+    private static String getLocale() {
+        return sCurrentLocale;
+    }
+
+    @CalledByNative
     private void onReceivedTouchIconUrl(String url, boolean precomposed) {
         mContentsClient.onReceivedTouchIconUrl(url, precomposed);
     }