[ReactNative] Add RCTBridgeDelegate

Summary:
Add a new bridge delegate protocol to allow a more flexible bridge configuration.

For now it just support the pre-existent configurations + providing the JavaScript
source to the bridge, that should allow pre-loading sources.

Examples/UIExplorer/UIExplorer/AppDelegate.m

@@ -14,49 +14,23 @@
 
 #import "AppDelegate.h"
 
+#import "RCTBridge.h"
+#import "RCTJavaScriptLoader.h"
 #import "RCTRootView.h"
 
+@interface AppDelegate() <RCTBridgeDelegate>
+
+@end
+
 @implementation AppDelegate
 
 - (BOOL)application:(__unused UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
 {
-  NSURL *jsCodeLocation;
+  RCTBridge *bridge = [[RCTBridge alloc] initWithDelegate:self
+                                            launchOptions:launchOptions];
 
-  /**
-   * Loading JavaScript code - uncomment the one you want.
-   *
-   * OPTION 1
-   * Load from development server. Start the server from the repository root:
-   *
-   * $ npm start
-   *
-   * To run on device, change `localhost` to the IP address of your computer
-   * (you can get this by typing `ifconfig` into the terminal and selecting the
-   * `inet` value under `en0:`) and make sure your computer and iOS device are
-   * on the same Wi-Fi network.
-   */
-
-  jsCodeLocation = [NSURL URLWithString:@"http://localhost:8081/Examples/UIExplorer/UIExplorerApp.ios.includeRequire.runModule.bundle?dev=true"];
-
-  /**
-   * OPTION 2
-   * Load from pre-bundled file on disk. To re-generate the static bundle, `cd`
-   * to your Xcode project folder and run
-   *
-   * $ curl 'http://localhost:8081/Examples/UIExplorer/UIExplorerApp.ios.includeRequire.runModule.bundle' -o main.jsbundle
-   *
-   * then add the `main.jsbundle` file to your project and uncomment this line:
-   */
-
-//  jsCodeLocation = [[NSBundle mainBundle] URLForResource:@"main" withExtension:@"jsbundle"];
-
-#if RUNNING_ON_CI
-   jsCodeLocation = [[NSBundle mainBundle] URLForResource:@"main" withExtension:@"jsbundle"];
-#endif
-
-  RCTRootView *rootView = [[RCTRootView alloc] initWithBundleURL:jsCodeLocation
-                                                      moduleName:@"UIExplorerApp"
-                                                   launchOptions:launchOptions];
+  RCTRootView *rootView = [[RCTRootView alloc] initWithBridge:bridge
+                                                   moduleName:@"UIExplorerApp"];
 
   self.window = [[UIWindow alloc] initWithFrame:[UIScreen mainScreen].bounds];
   UIViewController *rootViewController = [[UIViewController alloc] init];
@@ -66,4 +40,50 @@
   return YES;
 }
 
+- (NSURL *)sourceURLForBridge:(__unused RCTBridge *)bridge
+{
+    NSURL *sourceURL;
+
+    /**
+     * Loading JavaScript code - uncomment the one you want.
+     *
+     * OPTION 1
+     * Load from development server. Start the server from the repository root:
+     *
+     * $ npm start
+     *
+     * To run on device, change `localhost` to the IP address of your computer
+     * (you can get this by typing `ifconfig` into the terminal and selecting the
+     * `inet` value under `en0:`) and make sure your computer and iOS device are
+     * on the same Wi-Fi network.
+     */
+
+    sourceURL = [NSURL URLWithString:@"http://localhost:8081/Examples/UIExplorer/UIExplorerApp.ios.includeRequire.runModule.bundle?dev=true"];
+
+    /**
+     * OPTION 2
+     * Load from pre-bundled file on disk. To re-generate the static bundle, `cd`
+     * to your Xcode project folder and run
+     *
+     * $ curl 'http://localhost:8081/Examples/UIExplorer/UIExplorerApp.ios.includeRequire.runModule.bundle' -o main.jsbundle
+     *
+     * then add the `main.jsbundle` file to your project and uncomment this line:
+     */
+
+  //  sourceURL = [[NSBundle mainBundle] URLForResource:@"main" withExtension:@"jsbundle"];
+
+  #if RUNNING_ON_CI
+     sourceURL = [[NSBundle mainBundle] URLForResource:@"main" withExtension:@"jsbundle"];
+  #endif
+
+  return sourceURL;
+}
+
+- (void)loadSourceForBridge:(RCTBridge *)bridge
+                  withBlock:(RCTSourceLoadBlock)loadCallback
+{
+  [RCTJavaScriptLoader loadBundleAtURL:[self sourceURLForBridge:bridge]
+                            onComplete:loadCallback];
+}
+
 @end