Revert "Update Android Apps to use gradle"

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"
-    }
-
-    sourceSets.main.jni.srcDirs = [] //disable automatic ndk-build call
-    sourceSets.main.jniLibs.srcDir "src/main/libs"
-
-    productFlavors {
-        arm {}
-        arm64 {}
-        x86 {}
-        x86_64 {}
-        mips {}
-        mips64 {}
-    }
-
-    // make sure that app is built and shared libraries are copied to correct directories
-    applicationVariants.all{ variant ->
-
-        def buildNativeLib = task("${variant.name}_NativeLib", type:Exec) {
-            workingDir '../../../..' // top-level skia directory
-            commandLine constructBuildCommand(variant, "CopySampleAppDeps").split()
-            environment PATH: getPathWithDepotTools()
-            environment ANDROID_SDK_ROOT: getSDKPath()
-        }
-
-        if (!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
-        }
-    }
-}