Ensure that android "release" apps are signed with debug key

platform_tools/android/apps/sample_app/build.gradle

 apply plugin: 'com.android.application'
 
 android {
     compileSdkVersion 19
     buildToolsVersion "22.0.1"
 
     defaultConfig {
         applicationId "com.skia.sample_app"
         minSdkVersion 9
         targetSdkVersion 19
         versionCode 1
         versionName "1.0"
+        signingConfig signingConfigs.debug
     }
 
     sourceSets.main.jni.srcDirs = [] //disable automatic ndk-build call
     sourceSets.main.jniLibs.srcDir "src/main/libs"
 
     productFlavors {
         arm {}
         arm64 {}
         x86 {}
         x86_64 {}
@@ skipping 14 matching lines @@
         buildNativeLib.onlyIf { !project.hasProperty("suppressNativeBuild") }
 
         TaskCollection<Task> assembleTask
         assembleTask = project.tasks.matching {
             it.name.contains("assemble") &&
                     it.name.toLowerCase().endsWith(variant.name.toLowerCase())
         }
         assembleTask.getAt(0).dependsOn buildNativeLib
     }
 }