[iOS] For heron page, do not fire theme change event in Weex.
diff --git a/ios/sdk/WeexSDK/Sources/Model/WXSDKInstance.m b/ios/sdk/WeexSDK/Sources/Model/WXSDKInstance.m
index e3341d1..e069abf 100644
--- a/ios/sdk/WeexSDK/Sources/Model/WXSDKInstance.m
+++ b/ios/sdk/WeexSDK/Sources/Model/WXSDKInstance.m
@@ -1210,6 +1210,10 @@
     if (name && ![name isEqualToString:self.themeName]) {
         self.themeName = name;
         
+        if (self.isCustomRenderType) {
+            return;
+        }
+        
         // Recursively visit all components and notify that theme had changed.
         __weak WXSDKInstance* weakSelf = self;
         WXPerformBlockOnComponentThread(^{