Bump the default minSdkVersion to 19 (#125515)

See https://docs.flutter.dev/reference/supported-platforms

I don't expect this to break anything, but if it does we can revert and figure out what else needs to happen first.

Without this change, engine changes upstream will get flagged in default flutter created apps.

dev/integration_tests/android_custom_host_app/SampleApp/build.gradle

@@ -14,7 +14,7 @@ android {
 
     defaultConfig {
         applicationId "io.flutter.add2app"
-        minSdkVersion 16
+        minSdkVersion 19
         targetSdkVersion 31
         versionCode 1
         versionName "1.0"

dev/integration_tests/android_host_app_v2_embedding/app/build.gradle

@@ -14,7 +14,7 @@ android {
 
     defaultConfig {
         applicationId "io.flutter.add2app"
-        minSdkVersion 16
+        minSdkVersion 19
         targetSdkVersion 31
         versionCode 1
         versionName "1.0"

dev/integration_tests/deferred_components_test/android/component1/build.gradle

@@ -34,7 +34,7 @@ android {
     }
 
     defaultConfig {
-        minSdkVersion 16
+        minSdkVersion 19
         targetSdkVersion 31
         versionCode flutterVersionCode.toInteger()
         versionName flutterVersionName

dev/integration_tests/module_host_with_custom_build_v2_embedding/app/build.gradle

@@ -14,7 +14,7 @@ android {
 
     defaultConfig {
         applicationId "io.flutter.addtoapp"
-        minSdkVersion 16
+        minSdkVersion 19
         targetSdkVersion 31
         versionCode 1
         versionName "1.0"

packages/flutter_tools/gradle/src/main/groovy/flutter.groovy

@@ -47,7 +47,7 @@ class FlutterExtension {
     static int compileSdkVersion = 33
 
     /** Sets the minSdkVersion used by default in Flutter app projects. */
-    static int minSdkVersion = 16
+    static int minSdkVersion = 19
 
     /** Sets the targetSdkVersion used by default in Flutter app projects. */
     static int targetSdkVersion = 33

packages/flutter_tools/lib/src/android/gradle_utils.dart

@@ -39,7 +39,7 @@ const String templateKotlinGradlePluginVersion = '1.7.10';
 // `.android` is always regenerated after flutter pub get, so new versions are picked up after a
 // Flutter upgrade.
 const String compileSdkVersion = '33';
-const String minSdkVersion = '16';
+const String minSdkVersion = '19';
 const String targetSdkVersion = '33';
 const String ndkVersion = '23.1.7779620';
 

packages/flutter_tools/templates/module/android/deferred_component/build.gradle.tmpl

@@ -34,7 +34,7 @@ android {
     }
 
     defaultConfig {
-        minSdkVersion 16
+        minSdkVersion 19
         targetSdkVersion 31
         versionCode flutterVersionCode.toInteger()
         versionName flutterVersionName

packages/flutter_tools/test/integration.shard/test_data/deferred_components_config.dart

@@ -87,7 +87,7 @@ class DeferredComponentModule {
         }
 
         defaultConfig {
-            minSdkVersion 16
+            minSdkVersion 19
             targetSdkVersion 31
             versionCode flutterVersionCode.toInteger()
             versionName flutterVersionName

packages/flutter_tools/test/integration.shard/test_data/multidex_project.dart

@@ -162,7 +162,7 @@ class MultidexProject extends Project {
       defaultConfig {
           // TODO: Specify your own unique Application ID (https://developer.android.com/studio/build/application-id.html).
           applicationId "com.example.multidextest2"
-          minSdkVersion 16
+          minSdkVersion 19
           targetSdkVersion 30
           versionCode flutterVersionCode.toInteger()
           versionName flutterVersionName

packages/integration_test/android/build.gradle

@@ -34,7 +34,7 @@ android {
     }
 
     defaultConfig {
-        minSdkVersion 16
+        minSdkVersion 19
         testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
     }