title: Cannot resolve GoogleSignIn and GoogleSignInClient
body: <p>I am not able to use GoogleSignIn(<em>com.google.android.gms.auth.api.signin.GoogleSignIn</em>
  ) and GoogleSignInClient(<em>com.google.android.gms.auth.api.signin.GoogleSignInClient</em>
  ) while implementing Google Sign In in Android Studio while I can access other classes in App like</p>
  
  <pre><code>com.google.android.gms.auth.api.signin.GoogleSignInAccount;
  com.google.android.gms.auth.api.signin.GoogleSignInOptions;
  com.google.android.gms.common.SignInButton;
  </code></pre>
  
  <p>A strip down version of my build.gradle(app) file is as follow</p>
  
  <pre><code>android {
  
  }
  
  dependencies {
  
      compile 'com.google.android.gms:play-services-auth:11.4.2'
      compile('com.google.api-client:google-api-client-android:1.23.0') {
          exclude group: 'org.apache.httpcomponents'
      }
      compile('com.google.apis:google-api-services-gmail:v1-rev72-1.23.0') {
          exclude group: 'org.apache.httpcomponents'
      }
      implementation 'com.google.gms:google-services:3.1.2'
  }
  
  apply plugin: 'com.google.gms.google-services'
  </code></pre>
  
  <p>and my build.gradle(package) is</p>
  
  <pre><code>buildscript {
  
      dependencies {
          classpath 'com.android.tools.build:gradle:3.0.0'
          classpath 'com.google.gms:google-services:3.1.2'
      }
  }
  </code></pre>
  
  <p>Any help would be appreciated</p>