Add headers prop to Android WebViews

Summary:
Related to [issue #5418](https://github.com/facebook/react-native/issues/5418)

This is a follow-up to [this previous pull request.](https://github.com/facebook/react-native/pull/5419)

~~Adds a new ReactProp 'urlWithHeaders' to Android WebViews that takes an object with a 'url' string and a 'headers' map.~~

[Update] Adds a new prop 'source' to Android WebViews
```
{
   html: string,
   url: string,
   headers: map<string, string>,
}
```

Update: resolves TODO 8495359
Closes https://github.com/facebook/react-native/pull/5494

Reviewed By: svcscm

Differential Revision: D2881313

Pulled By: nicklockwood

fb-gh-sync-id: 7cad8490d4932d0a7ef559165f3ec279d873c537

Libraries/Components/WebView/WebView.android.js

@@ -17,6 +17,7 @@ var StyleSheet = require('StyleSheet');
 var UIManager = require('UIManager');
 var View = require('View');
 
+var deprecatedPropType = require('deprecatedPropType');
 var keyMirror = require('keyMirror');
 var merge = require('merge');
 var requireNativeComponent = require('requireNativeComponent');
@@ -44,14 +45,29 @@ var WebView = React.createClass({
     onLoadEnd: PropTypes.func,
     onLoadStart: PropTypes.func,
     onError: PropTypes.func,
-    url: PropTypes.string,
-    html: PropTypes.string,
     automaticallyAdjustContentInsets: PropTypes.bool,
     contentInset: EdgeInsetsPropType,
     onNavigationStateChange: PropTypes.func,
     startInLoadingState: PropTypes.bool, // force WebView to show loadingView on first load
     style: View.propTypes.style,
 
+    html: deprecatedPropType(
+      PropTypes.string,
+      'Use the `source` prop instead.'
+    ),
+
+    url: deprecatedPropType(
+      PropTypes.string,
+      'Use the `source` prop instead.'
+    ),
+
+    /**
+     * Used on Android only, provides html or url with optional headers to the WebView.
+     * `{ html: string, uri: string, headers: map<string, string> }`
+     * @platform android
+     */
+    source: PropTypes.object,
+
     /**
      * Used on Android only, JS is enabled by default for WebView on iOS
      * @platform android
@@ -127,13 +143,19 @@ var WebView = React.createClass({
       domStorageEnabled = this.props.domStorageEnabledAndroid;
     }
 
+    var source = this.props.source || {};
+    if (this.props.html) {
+      source.html = this.props.html;
+    } else if (this.props.url) {
+      source.uri = this.props.url;
+    }
+
     var webView =
       <RCTWebView
         ref={RCT_WEBVIEW_REF}
         key="webViewKey"
         style={webViewStyles}
-        url={this.props.url}
-        html={this.props.html}
+        source={source}
         injectedJavaScript={this.props.injectedJavaScript}
         userAgent={this.props.userAgent}
         javaScriptEnabled={javaScriptEnabled}

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

@@ -9,10 +9,6 @@
 
 package com.facebook.react.views.webview;
 
-import javax.annotation.Nullable;
-
-import java.util.Map;
-
 import android.graphics.Bitmap;
 import android.os.Build;
 import android.os.SystemClock;
@@ -27,16 +23,23 @@ import com.facebook.react.bridge.Arguments;
 import com.facebook.react.bridge.LifecycleEventListener;
 import com.facebook.react.bridge.ReactContext;
 import com.facebook.react.bridge.ReadableArray;
+import com.facebook.react.bridge.ReadableMap;
+import com.facebook.react.bridge.ReadableMapKeySetIterator;
 import com.facebook.react.bridge.WritableMap;
 import com.facebook.react.common.MapBuilder;
 import com.facebook.react.common.build.ReactBuildConfig;
-import com.facebook.react.uimanager.annotations.ReactProp;
 import com.facebook.react.uimanager.SimpleViewManager;
 import com.facebook.react.uimanager.ThemedReactContext;
 import com.facebook.react.uimanager.UIManagerModule;
+import com.facebook.react.uimanager.annotations.ReactProp;
 import com.facebook.react.uimanager.events.Event;
 import com.facebook.react.uimanager.events.EventDispatcher;
 
+import java.util.HashMap;
+import java.util.Map;
+
+import javax.annotation.Nullable;
+
 /**
  * Manages instances of {@link WebView}
  *
@@ -271,31 +274,28 @@ public class ReactWebViewManager extends SimpleViewManager<WebView> {
     ((ReactWebView) view).setInjectedJavaScript(injectedJavaScript);
   }
 
-  @ReactProp(name = "html")
-  public void setHtml(WebView view, @Nullable String html) {
-    if (html != null) {
-      view.loadData(html, HTML_MIME_TYPE, HTML_ENCODING);
-    } else {
-      view.loadUrl(BLANK_URL);
-    }
-  }
-
-  @ReactProp(name = "url")
-  public void setUrl(WebView view, @Nullable String url) {
-    // TODO(8495359): url and html are coupled as they both call loadUrl, therefore in case when
-    // property url is removed in favor of property html being added in single transaction we may
-    // end up in a state when blank url is loaded as it depends on the order of update operations!
-
-    String currentUrl = view.getUrl();
-    if (currentUrl != null && currentUrl.equals(url)) {
-      // We are already loading it so no need to stomp over it and start again
-      return;
-    }
-    if (url != null) {
-      view.loadUrl(url);
-    } else {
-      view.loadUrl(BLANK_URL);
+  @ReactProp(name = "source")
+  public void setSource(WebView view, @Nullable ReadableMap source) {
+    if (source != null) {
+      if (source.hasKey("html")) {
+        view.loadData(source.getString("html"), HTML_MIME_TYPE, HTML_ENCODING);
+        return;
+      }
+      if (source.hasKey("uri")) {
+        HashMap<String, String> headerMap = new HashMap<>();
+        if (source.hasKey("headers")) {
+          ReadableMap headers = source.getMap("headers");
+          ReadableMapKeySetIterator iter = headers.keySetIterator();
+          while (iter.hasNextKey()) {
+            String key = iter.nextKey();
+            headerMap.put(key, headers.getString(key));
+          }
+        }
+        view.loadUrl(source.getString("uri"), headerMap);
+        return;
+      }
     }
+    view.loadUrl(BLANK_URL);
   }
 
   @Override