Add support for deleting a shared preference (#1018)

Summary:
This change makes it possible to remove preferences. I also added a `Delete` context menu option to `DataInspector` because I needed it to implement this feature. passy confirmed that it makes sense to add this because delete is a common action.

Fixes https://github.com/facebook/flipper/issues/451
Pull Request resolved: https://github.com/facebook/flipper/pull/1018

Reviewed By: jknoxville

Differential Revision: D21086308

Pulled By: passy

fbshipit-source-id: 551ff0908d5e6c93f58d6012b42e1ee3531de997

desktop/plugins/shared_preferences/index.js

@@ -209,6 +209,21 @@ export default class extends FlipperPlugin<SharedPreferencesState> {
     });
   };
 
+  onSharedPreferencesDeleted = (path: Array<string>) => {
+    this.client
+      .call('deleteSharedPreference', {
+        sharedPreferencesName: this.state.selectedPreferences,
+        preferenceName: path[0],
+      })
+      .then((results: SharedPreferences) => {
+        const update = {
+          name: this.state.selectedPreferences,
+          preferences: results,
+        };
+        this.dispatchAction({update, type: 'UpdateSharedPreferences'});
+      });
+  };
+
   render() {
     const selectedPreferences = this.state.selectedPreferences;
     if (selectedPreferences == null) {
@@ -241,6 +256,7 @@ export default class extends FlipperPlugin<SharedPreferencesState> {
             <ManagedDataInspector
               data={entry.preferences}
               setValue={this.onSharedPreferencesChanged}
+              onDelete={this.onSharedPreferencesDeleted}
             />
           </InspectorColumn>
           <ChangelogColumn>