RN: Delete Systrace.swizzleJSON

Reviewed By: TheSavior

Differential Revision: D7207460

fbshipit-source-id: 14b1174d6a5c75e1acba7272376d1c462bc13cb6

Libraries/Performance/Systrace.js

@@ -182,65 +182,6 @@ const Systrace = {
         global.nativeTraceCounter(TRACE_TAG_REACT_APPS, profileName, value);
     }
   },
-
-  /* This is not called by default due to perf overhead but it's useful
-     if you want to find traces which spend too much time in JSON. */
-  swizzleJSON() {
-    Systrace.measureMethods(JSON, 'JSON', ['parse', 'stringify']);
-  },
-
-  /**
-   * Measures multiple methods of a class. For example, you can do:
-   * Systrace.measureMethods(JSON, 'JSON', ['parse', 'stringify']);
-   *
-   * @param object
-   * @param objectName
-   * @param methodNames Map from method names to method display names.
-   */
-  measureMethods(
-    object: any,
-    objectName: string,
-    methodNames: Array<string>,
-  ): void {
-    if (!__DEV__) {
-      return;
-    }
-
-    methodNames.forEach(methodName => {
-      object[methodName] = Systrace.measure(
-        objectName,
-        methodName,
-        object[methodName],
-      );
-    });
-  },
-
-  /**
-   * Returns an profiled version of the input function. For example, you can:
-   * JSON.parse = Systrace.measure('JSON', 'parse', JSON.parse);
-   *
-   * @param objName
-   * @param fnName
-   * @param {function} func
-   * @return {function} replacement function
-   */
-  measure(objName: string, fnName: string, func: any): any {
-    if (!__DEV__) {
-      return func;
-    }
-
-    const profileName = `${objName}.${fnName}`;
-    return function() {
-      if (!_enabled) {
-        return func.apply(this, arguments);
-      }
-
-      Systrace.beginEvent(profileName);
-      const ret = func.apply(this, arguments);
-      Systrace.endEvent();
-      return ret;
-    };
-  },
 };
 
 if (__DEV__) {