Came across a topic with similar problem, but was unable to solve it.
Integrated Admob ads in Unity app for ios and loaded the project in XCode. Added framework GoogleMobileAds simply dragging it into the project window. Unfortunately when you build the project the error is displayed.
I tryed replace GoogleMobileAds.h
on #import <GoogleMobileAds/GoogleMobileAds.h>
in GADUNativeCustomTemplateAd.h but it not help me.
Used Google Mobile Ads Unity Plugin v3.0.4 Xcode v. 7.3.1 Error: umbrella header googlemobileads h not found 1 img 2 img