[google_maps_flutter] Allow BitmapDescriptor scaling override (#1737)

* Allow BitmapDescriptor scaling override

* Updated the pubspec.yml and changelog files

packages/google_maps_flutter/CHANGELOG.md

diff --git a/packages/google_maps_flutter/CHANGELOG.md b/packages/google_maps_flutter/CHANGELOG.md
index 7cc7628..aac078f 100644
--- a/packages/google_maps_flutter/CHANGELOG.md
+++ b/packages/google_maps_flutter/CHANGELOG.md
@@ -1,3 +1,7 @@
+## 0.5.19
+
+* Allow BitmapDescriptor scaling override
+
 ## 0.5.18
 
 * Fixed build issue on iOS.

packages/google_maps_flutter/lib/src/bitmap.dart

diff --git a/packages/google_maps_flutter/lib/src/bitmap.dart b/packages/google_maps_flutter/lib/src/bitmap.dart
index 2027eee..e239956 100644
--- a/packages/google_maps_flutter/lib/src/bitmap.dart
+++ b/packages/google_maps_flutter/lib/src/bitmap.dart
@@ -59,6 +59,13 @@
     AssetBundle bundle,
     String package,
   }) async {
+    if (configuration.devicePixelRatio != null) {
+      return BitmapDescriptor._(<dynamic>[
+        'fromAssetImage',
+        assetName,
+        configuration.devicePixelRatio,
+      ]);
+    }
     final AssetImage assetImage =
         AssetImage(assetName, package: package, bundle: bundle);
     final AssetBundleImageKey assetBundleImageKey =

packages/google_maps_flutter/pubspec.yaml

diff --git a/packages/google_maps_flutter/pubspec.yaml b/packages/google_maps_flutter/pubspec.yaml
index 2f35db1..91f55db 100644
--- a/packages/google_maps_flutter/pubspec.yaml
+++ b/packages/google_maps_flutter/pubspec.yaml
@@ -2,7 +2,7 @@
 description: A Flutter plugin for integrating Google Maps in iOS and Android applications.
 author: Flutter Team <flutter-dev@googlegroups.com>
 homepage: https://github.com/flutter/plugins/tree/master/packages/google_maps_flutter
-version: 0.5.18
+version: 0.5.19
 
 dependencies:
   flutter: