M webclient/build-tests.xml

- re-activate some tests

M webclient/classes_spec/org/mozilla/webclient/impl/wrapper_native/PreferencesImpl.java

- Make null an acceptable argument for prefValue.  Make it mean, remove
  the pref.

M webclient/src_moz/PreferencesImpl.cpp

- make a null prefValue argument to nativeSetUnicharPref mean, ClearPref().

java/webclient/classes_spec/org/mozilla/webclient/impl/wrapper_native/PreferencesImpl.java

@@ -106,9 +106,6 @@ public void setPref(String prefName, String prefValue)
     if (null == prefName) {
         return;
     }
-    if (null == prefValue) {
-        return;
-    }
     // determine the type of pref value: String, boolean, integer
     try {
         Integer intVal = Integer.valueOf(prefValue);
@@ -116,7 +113,8 @@ public void setPref(String prefName, String prefValue)
     }
     catch (NumberFormatException e) {
         // it's not an integer
-        if (prefValue.equals("true") || prefValue.equals("false")) {
+        if (null != prefValue &&
+            (prefValue.equals("true") || prefValue.equals("false"))) {
             Boolean boolVal = Boolean.valueOf(prefValue);
             nativeSetBoolPref(getWrapperFactory().getNativeContext(), prefName, 
                               boolVal.booleanValue());

java/webclient/src_moz/PreferencesImpl.cpp

@@ -111,22 +111,28 @@ Java_org_mozilla_webclient_impl_wrapper_1native_PreferencesImpl_nativeSetUnichar
     
     const char	*	prefNameChars = (char *)::util_GetStringUTFChars(env, 
                                                                      prefName);
-    const jchar	*	prefValueChars = (jchar *)::util_GetStringChars(env, 
-                                                                    prefValue);
-    if (nsnull == prefNameChars) {
-        ::util_ThrowExceptionToJava(env, "nativeSetUnicharPref: unable to extract Java string for pref name");
-        rv = NS_ERROR_NULL_POINTER;
-        goto OMWIWNPINSUP_CLEANUP;
+    const jchar	*	prefValueChars = nsnull;
+    if (nsnull != prefValue) {
+        prefValueChars = 
+            (jchar *)::util_GetStringChars(env, prefValue);
+        if (nsnull == prefNameChars) {
+            ::util_ThrowExceptionToJava(env, "nativeSetUnicharPref: unable to extract Java string for pref name");
+            rv = NS_ERROR_NULL_POINTER;
+            goto OMWIWNPINSUP_CLEANUP;
+        }
+        if (nsnull == prefValueChars) {
+            ::util_ThrowExceptionToJava(env, "nativeSetUnicharPref: unable to extract Java string for pref value");
+            rv = NS_ERROR_NULL_POINTER;
+            goto OMWIWNPINSUP_CLEANUP;
+        }
+        
+        rv = prefs->SetUnicharPref(prefNameChars, 
+                                   (const PRUnichar *) prefValueChars);
     }
-    if (nsnull == prefValueChars) {
-        ::util_ThrowExceptionToJava(env, "nativeSetUnicharPref: unable to extract Java string for pref value");
-        rv = NS_ERROR_NULL_POINTER;
-        goto OMWIWNPINSUP_CLEANUP;
+    else {
+        rv = prefs->ClearUserPref(prefNameChars);
     }
 
-    rv = prefs->SetUnicharPref(prefNameChars, 
-                               (const PRUnichar *) prefValueChars);
-
  OMWIWNPINSUP_CLEANUP:
     
     ::util_ReleaseStringUTFChars(env, prefName, prefNameChars);