WebView didn't get canGoBack correctly

Have you read the Bugs section of the Contributing to React Native Guide?

(Write your answer here.)

Environment

1. react-native -v: react-native-cli: 2.0.1 react-native: 0.45.1
2. node -v: v8.1.2
3. npm -v: 5.0.3
4. yarn --version (if you use Yarn): 0.24.6

Then, specify:

1. Target Platform (e.g. iOS, Android): iOS
2. Development Operating System (e.g. macOS Sierra, Windows 10): macOS Sierra
3. Build tools (Xcode or Android Studio version, iOS or Android SDK version, if relevant): iOS >8.0 Xcode 8.3.3

Steps to Reproduce

1.add an webView and a button call webView’s goBack 2.view some page and go back 3.check whether the canGoBack is right

Expected Behavior

the canGoBack is false when back to the first page the canGoBack is true when viewing deeper page

Actual Behavior

the canGoBack sometime is false at the page which is not the first loaded page.

[ashconnell]

Just confirming this is a bug.

To Reproduce:

1. Instantiate a WebView like so

    <WebView
        source={{ uri: 'https://www.google.com' }}
        onNavigationStateChange={ ({ canGoback }) => console.log(canGoBack) }
    />

1. Click anything (eg the banner image) to navigate to a new page

What Happens: The console logs false as the next page begins to load, and then true after the page has loaded

What should happen: The console logs true as the next page begins to load and true after the page has loaded

[RLesser]

Still happening, this especially hurts because there’s no other way (that I know of) to correctly tell if the current webview can go back.