- Add DevSetting native module (making it cross-platform) (#24441)

Summary:
React Native has a `NativeModule` to manipulate programmatically the dev menu options (live reload, hot reload, remote debugging, etc), called [`DevSettings`](https://github.com/facebook/react-native/blob/master/React/Modules/RCTDevSettings.mm#L120). However this module is only available for iOS.

This PR brings the same `DevSettings` for Android, making it a cross-platform NativeModule.

Motivation: Right now if your app needs to programmatically reload RN, one option is to install [`react-native-restart`](https://www.npmjs.com/package/react-native-restart). It's a tiny dependency, but it's annoying to have to install it, while the code to do so is inside RN codebase. According to NPM, react-native-restart has ~12k weekly downloads, shows it's a recurring feature for many apps (my case).

Thus making `NativeModules.DevSettings` is a small increment in the codebase, just exposing the dev menu methods, to improve the Development Experience

[Android] [Added] - Add DevSetting native module (making it cross-platform)

With expection of `setIsShakeToShowDevMenuEnabled`, the following methods will be available for both platforms:
* reload
* setHotLoadingEnabled
* setIsDebuggingRemotely
* setIsShakeToShowDevMenuEnabled
* setLiveReloadEnabled
* setProfilingEnabled
* toggleElementInspector
Pull Request resolved: https://github.com/facebook/react-native/pull/24441

Differential Revision: D14932751

Pulled By: cpojer

fbshipit-source-id: 465e6a89c3beb5fd1ea22e80ea02e9438f596a09

ReactAndroid/src/main/java/com/facebook/react/devsupport/DevSupportManagerImpl.java

@@ -1040,6 +1040,90 @@ public class DevSupportManagerImpl implements
     mDevServerHelper.closeInspectorConnection();
   }
 
+  @Override
+  public void setHotModuleReplacementEnabled(final boolean isHotModuleReplacementEnabled) {
+    if (!mIsDevSupportEnabled) {
+      return;
+    }
+
+    UiThreadUtil.runOnUiThread(
+      new Runnable() {
+        @Override
+        public void run() {
+          mDevSettings.setHotModuleReplacementEnabled(isHotModuleReplacementEnabled);
+          handleReloadJS();
+        }
+      }
+    );
+  }
+
+  @Override
+  public void setRemoteJSDebugEnabled(final boolean isRemoteJSDebugEnabled) {
+    if (!mIsDevSupportEnabled) {
+      return;
+    }
+
+    UiThreadUtil.runOnUiThread(
+      new Runnable() {
+        @Override
+        public void run() {
+          mDevSettings.setRemoteJSDebugEnabled(isRemoteJSDebugEnabled);
+          handleReloadJS();
+        }
+      }
+    );
+  }
+
+  @Override
+  public void setReloadOnJSChangeEnabled(final boolean isReloadOnJSChangeEnabled) {
+    if (!mIsDevSupportEnabled) {
+      return;
+    }
+
+    UiThreadUtil.runOnUiThread(
+      new Runnable() {
+        @Override
+        public void run() {
+          mDevSettings.setReloadOnJSChangeEnabled(isReloadOnJSChangeEnabled);
+          handleReloadJS();
+        }
+      }
+    );
+  }
+
+  @Override
+  public void setFpsDebugEnabled(final boolean isFpsDebugEnabled) {
+    if (!mIsDevSupportEnabled) {
+      return;
+    }
+
+    UiThreadUtil.runOnUiThread(
+      new Runnable() {
+        @Override
+        public void run() {
+          mDevSettings.setFpsDebugEnabled(isFpsDebugEnabled);
+        }
+      }
+    );
+  }
+
+  @Override
+  public void toggleElementInspector() {
+    if (!mIsDevSupportEnabled) {
+      return;
+    }
+
+    UiThreadUtil.runOnUiThread(
+      new Runnable() {
+        @Override
+        public void run() {
+          mDevSettings.setElementInspectorEnabled(!mDevSettings.isElementInspectorEnabled());
+          mReactInstanceManagerHelper.toggleElementInspector();
+        }
+      }
+    );
+  }
+
   private void reload() {
     UiThreadUtil.assertOnUiThread();
 

ReactAndroid/src/main/java/com/facebook/react/devsupport/DisabledDevSupportManager.java

@@ -78,6 +78,31 @@ public class DisabledDevSupportManager implements DevSupportManager {
 
   }
 
+  @Override
+  public void setHotModuleReplacementEnabled(boolean isHotModuleReplacementEnabled) {
+
+  }
+
+  @Override
+  public void setRemoteJSDebugEnabled(boolean isRemoteJSDebugEnabled) {
+
+  }
+
+  @Override
+  public void setReloadOnJSChangeEnabled(boolean isReloadOnJSChangeEnabled) {
+
+  }
+
+  @Override
+  public void setFpsDebugEnabled(boolean isFpsDebugEnabled) {
+
+  }
+
+  @Override
+  public void toggleElementInspector() {
+
+  }
+
   @Override
   public boolean getDevSupportEnabled() {
     return false;
@@ -162,7 +187,7 @@ public class DisabledDevSupportManager implements DevSupportManager {
 
   @Override
   public void registerErrorCustomizer(ErrorCustomizer errorCustomizer) {
-    
+
   }
 
   @Override

ReactAndroid/src/main/java/com/facebook/react/devsupport/interfaces/DevSupportManager.java

@@ -45,6 +45,11 @@ public interface DevSupportManager extends NativeModuleCallExceptionHandler {
   void handleReloadJS();
   void reloadJSFromServer(final String bundleURL);
   void isPackagerRunning(PackagerStatusCallback callback);
+  void setHotModuleReplacementEnabled(final boolean isHotModuleReplacementEnabled);
+  void setRemoteJSDebugEnabled(final boolean isRemoteJSDebugEnabled);
+  void setReloadOnJSChangeEnabled(final boolean isReloadOnJSChangeEnabled);
+  void setFpsDebugEnabled(final boolean isFpsDebugEnabled);
+  void toggleElementInspector();
   @Nullable File downloadBundleResourceFromUrlSync(
       final String resourceURL,
       final File outputFile);