@Override
    public boolean equals(Object o) {
        if (!(o instanceof CustomTabsSessionToken)) return false;
        CustomTabsSessionToken other = (CustomTabsSessionToken) o;
        if (mSessionId != null && other.getId() != null) return mSessionId.equals(other.getId());

        return other.getCallbackBinder() != null &&
               other.getCallbackBinder().equals(mCallbackBinder.asBinder());
    }
Provides browsers a way to generate a mock {@link CustomTabsSessionToken} for testing
purposes.

@return A mock token with no functionality.
customtabs/src/android/support/customtabs/CustomTabsSessionToken.java