Bug 1255227 - Part 1: Stop using deprecated android-sdk-manager Gradle plugin. r=sebastian

This was only ever used to automatically fetch Android SDK
dependencies in the android-gradle-dependencies job in Task Cluster.
That function is now provided by newer Android-Gradle build plugins.

MozReview-Commit-ID: Adrxm2rAPlZ

--HG--
extra : rebase_source : 6cccb53e2ebc2642ee6c61ef13fcb6d8321b67cf

build.gradle

@@ -47,7 +47,7 @@ buildscript {
                 url repository
             }
         }
-        // For android-sdk-manager SNAPSHOT releases.
+        // For dexcount-gradle-plugin and other in tree plugins.
         maven {
             url "file://${gradle.mozconfig.topsrcdir}/mobile/android/gradle/m2repo"
         }
@@ -60,7 +60,6 @@ buildscript {
             exclude module: 'guava'
         }
         // Provided in tree.
-        classpath 'com.jakewharton.sdkmanager:gradle-plugin:1.5.0-SNAPSHOT'
         classpath 'com.getkeepsafe.dexcount:dexcount-gradle-plugin:0.6.1'
     }
 }

mobile/android/app/build.gradle

 buildDir "${topobjdir}/gradle/build/mobile/android/app"
 
-apply plugin: 'android-sdk-manager' // Must come before 'com.android.*'.
 apply plugin: 'com.android.application'
 apply plugin: 'checkstyle'
 apply plugin: 'com.getkeepsafe.dexcount'

mobile/android/geckoview/build.gradle

 buildDir "${topobjdir}/gradle/build/mobile/android/geckoview"
 
-apply plugin: 'android-sdk-manager' // Must come before 'com.android.*'.
 apply plugin: 'com.android.library'
 
 def VERSION_NAME = '0.0.1'