Rename WebView postMessage method to postMessageNative.

Libraries/Components/WebView/WebView.ios.js

@@ -237,11 +237,11 @@ class WebView extends React.Component {
      */
     onNavigationStateChange: PropTypes.func,
     /**
-     * A function that is invoked when the webview calls `window.postMessage`.
-     * Setting this property will inject a `postMessage` global into your
+     * A function that is invoked when the webview calls `window.postMessageNative`.
+     * Setting this property will inject a `postMessageNative` global into your
      * webview, but will still call pre-existing values of `postMessage`.
      *
-     * `window.postMessage` accepts one argument, `data`, which will be
+     * `window.postMessageNative` accepts one argument, `data`, which will be
      * available on the event object, `event.nativeEvent.data`. `data`
      * must be a string.
      */

React/Views/RCTWebView.m

@@ -292,8 +292,7 @@ - (void)webViewDidFinishLoad:(UIWebView *)webView
     }
     #endif
     NSString *source = [NSString stringWithFormat:
-      @"window.originalPostMessage = window.postMessage;"
-      "window.postMessage = function(data) {"
+      @"window.postMessageNative = function(data) {"
         "window.location = '%@://%@?' + encodeURIComponent(String(data));"
       "};", RCTJSNavigationScheme, RCTJSPostMessageHost
     ];

ReactAndroid/src/main/java/com/facebook/react/views/webview/ReactWebViewManager.java

@@ -295,8 +295,7 @@ public void onReceiveValue(String value) {
         }
 
         loadUrl("javascript:(" +
-          "window.originalPostMessage = window.postMessage," +
-          "window.postMessage = function(data) {" +
+          "window.postMessageNative = function(data) {" +
             BRIDGE_NAME + ".postMessage(String(data));" +
           "}" +
         ")");