Implement nativePerformanceNow to improve Profiler API results (#27885)

Summary:
When experimenting with React Profiler API (https://reactjs.org/docs/profiler.html), I noticed that durations are integers without a debugger, but they are doubles with higher precision when debugger is attached. After digging into React Profiler code, I found out that it's using `performance.now()` to accumulate execution times of individual units of work. Since this method does not exist in React Native, it falls back to Javascript `Date`, leading to imprecise results.

This PR introduces `global.nativePerformanceNow` function which returns precise native time, and a very basic `performance` polyfill with `now` function.

This will greatly improve React Profiler API results, which is essential for profiling and benchmark tools.

Solves https://github.com/facebook/react-native/issues/27274

## Changelog

[General] [Added] - Implement `nativePerformanceNow` and `performance.now()`
Pull Request resolved: https://github.com/facebook/react-native/pull/27885

Test Plan:
```
const initialTime = global.performance.now();
setTimeout(() => {
  const newTime = global.performance.now();
  console.warn('duration', newTime - initialTime);
}, 1000);
```

### Android + Hermes

![Screenshot_1580198068](https://user-images.githubusercontent.com/13116854/73245757-af0d6c80-41b5-11ea-8130-dde14ebd41a3.png)

### Android + JSC

![Screenshot_1580199089](https://user-images.githubusercontent.com/13116854/73246157-92256900-41b6-11ea-87a6-ac222383200c.png)

### iOS

![Simulator Screen Shot - iPhone 8 - 2020-01-28 at 10 06 49](https://user-images.githubusercontent.com/13116854/73245871-f136ae00-41b5-11ea-9e31-b1eff5717e62.png)

Reviewed By: ejanzer

Differential Revision: D19888289

Pulled By: rickhanlonii

fbshipit-source-id: ab8152382da9aee9b4b3c76f096e45d40f55da6c

Libraries/Core/InitializeCore.js

@@ -29,6 +29,7 @@
 const start = Date.now();
 
 require('./setUpGlobals');
+require('./setUpPerformance');
 require('./setUpSystrace');
 require('./setUpErrorHandling');
 require('./polyfillPromise');

Libraries/Core/setUpPerformance.js

@@ -0,0 +1,26 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * @flow strict-local
+ * @format
+ */
+
+'use strict';
+
+if (!global.performance) {
+  global.performance = {};
+}
+
+/**
+ * Returns a double, measured in milliseconds.
+ * https://developer.mozilla.org/en-US/docs/Web/API/Performance/now
+ */
+if (typeof global.performance.now !== 'function') {
+  global.performance.now = function() {
+    const performanceNow = global.nativePerformanceNow || Date.now;
+    return performanceNow();
+  };
+}

Libraries/Performance/Systrace.js

@@ -87,11 +87,25 @@ const userTimingPolyfill = __DEV__
     }
   : null;
 
+function installPerformanceHooks(polyfill) {
+  if (polyfill) {
+    if (global.performance === undefined) {
+      global.performance = {};
+    }
+
+    Object.keys(polyfill).forEach(methodName => {
+      if (typeof global.performance[methodName] !== 'function') {
+        global.performance[methodName] = polyfill[methodName];
+      }
+    });
+  }
+}
+
 const Systrace = {
   installReactHook() {
     if (_enabled) {
       if (__DEV__) {
-        global.performance = userTimingPolyfill;
+        installPerformanceHooks(userTimingPolyfill);
       }
     }
     _canInstallReactHook = true;
@@ -108,8 +122,8 @@ const Systrace = {
             global.nativeTraceEndLegacy(TRACE_TAG_JS_VM_CALLS);
         }
         if (_canInstallReactHook) {
-          if (enabled && global.performance === undefined) {
-            global.performance = userTimingPolyfill;
+          if (enabled) {
+            installPerformanceHooks(userTimingPolyfill);
           }
         }
       }

React/CxxBridge/JSCExecutorFactory.mm

@@ -24,6 +24,13 @@ std::unique_ptr<JSExecutor> JSCExecutorFactory::createJSExecutor(
       _RCTLogJavaScriptInternal(static_cast<RCTLogLevel>(logLevel), [NSString stringWithUTF8String:message.c_str()]);
     };
     react::bindNativeLogger(runtime, iosLoggingBinder);
+
+    react::PerformanceNow iosPerformanceNowBinder = []() {
+      // CACurrentMediaTime() returns the current absolute time, in seconds
+      return CACurrentMediaTime() * 1000;
+    };
+    react::bindNativePerformanceNow(runtime, iosPerformanceNowBinder);
+
     // Wrap over the original runtimeInstaller
     if (runtimeInstaller) {
       runtimeInstaller(runtime);

ReactAndroid/src/main/java/com/facebook/hermes/reactexecutor/OnLoad.cpp

@@ -14,6 +14,7 @@
 #include <react/jni/JReactMarker.h>
 #include <react/jni/JSLogging.h>
 #include <react/jni/JavaScriptExecutorHolder.h>
+#include <react/jni/NativeTime.h>
 
 #include <memory>
 
@@ -48,6 +49,10 @@ static void installBindings(jsi::Runtime &runtime) {
       static_cast<void (*)(const std::string &, unsigned int)>(
           &reactAndroidLoggingHook);
   react::bindNativeLogger(runtime, androidLogger);
+
+  react::PerformanceNow androidNativePerformanceNow =
+      static_cast<double (*)()>(&reactAndroidNativePerformanceNowHook);
+  react::bindNativePerformanceNow(runtime, androidNativePerformanceNow);
 }
 
 class HermesExecutorHolder

ReactAndroid/src/main/java/com/facebook/react/jscexecutor/OnLoad.cpp

@@ -11,6 +11,7 @@
 #include <react/jni/JReactMarker.h>
 #include <react/jni/JSLogging.h>
 #include <react/jni/JavaScriptExecutorHolder.h>
+#include <react/jni/NativeTime.h>
 #include <react/jni/ReadableNativeMap.h>
 
 #include <memory>
@@ -30,6 +31,10 @@ class JSCExecutorFactory : public JSExecutorFactory {
           static_cast<void (*)(const std::string &, unsigned int)>(
               &reactAndroidLoggingHook);
       react::bindNativeLogger(runtime, androidLogger);
+
+      react::PerformanceNow androidNativePerformanceNow =
+          static_cast<double (*)()>(&reactAndroidNativePerformanceNowHook);
+      react::bindNativePerformanceNow(runtime, androidNativePerformanceNow);
     };
     return std::make_unique<JSIExecutor>(
         jsc::makeJSCRuntime(),

ReactAndroid/src/main/jni/react/jni/NativeTime.cpp

@@ -0,0 +1,26 @@
+/*
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+#include "NativeTime.h"
+#include <chrono>
+
+namespace facebook {
+namespace react {
+
+double reactAndroidNativePerformanceNowHook() {
+  auto time = std::chrono::steady_clock::now();
+  auto duration = std::chrono::duration_cast<std::chrono::nanoseconds>(
+                      time.time_since_epoch())
+                      .count();
+
+  constexpr double NANOSECONDS_IN_MILLISECOND = 1000000.0;
+
+  return duration / NANOSECONDS_IN_MILLISECOND;
+}
+
+} // namespace react
+} // namespace facebook

ReactAndroid/src/main/jni/react/jni/NativeTime.h

@@ -0,0 +1,16 @@
+/*
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+#pragma once
+
+namespace facebook {
+namespace react {
+
+double reactAndroidNativePerformanceNowHook();
+
+} // namespace react
+} // namespace facebook

ReactCommon/jsiexecutor/jsireact/JSIExecutor.cpp

@@ -483,5 +483,20 @@ void bindNativeLogger(Runtime &runtime, Logger logger) {
           }));
 }
 
+void bindNativePerformanceNow(Runtime &runtime, PerformanceNow performanceNow) {
+  runtime.global().setProperty(
+      runtime,
+      "nativePerformanceNow",
+      Function::createFromHostFunction(
+          runtime,
+          PropNameID::forAscii(runtime, "nativePerformanceNow"),
+          0,
+          [performanceNow = std::move(performanceNow)](
+              jsi::Runtime &runtime,
+              const jsi::Value &,
+              const jsi::Value *args,
+              size_t count) { return Value(performanceNow()); }));
+}
+
 } // namespace react
 } // namespace facebook

ReactCommon/jsiexecutor/jsireact/JSIExecutor.h

@@ -135,5 +135,10 @@ class JSIExecutor : public JSExecutor {
 using Logger =
     std::function<void(const std::string &message, unsigned int logLevel)>;
 void bindNativeLogger(jsi::Runtime &runtime, Logger logger);
+
+using PerformanceNow = std::function<double()>;
+void bindNativePerformanceNow(
+    jsi::Runtime &runtime,
+    PerformanceNow performanceNow);
 } // namespace react
 } // namespace facebook