Move the embedded view preview flag check to a common function.

shell/platform/darwin/ios/framework/Source/FlutterEngine.mm

@@ -296,8 +296,6 @@ - (BOOL)createShell:(NSString*)entrypoint libraryURI:(NSString*)libraryURI {
       threadLabel.UTF8String,  // label
       shell::ThreadHost::Type::UI | shell::ThreadHost::Type::GPU | shell::ThreadHost::Type::IO};
 
-  bool embedded_views_preview_enabled = [[[NSBundle mainBundle]
-      objectForInfoDictionaryKey:@(shell::kEmbeddedViewsPreview)] boolValue];
   // Lambda captures by pointers to ObjC objects are fine here because the
   // create call is
   // synchronous.
@@ -310,7 +308,7 @@ - (BOOL)createShell:(NSString*)entrypoint libraryURI:(NSString*)libraryURI {
     return std::make_unique<shell::Rasterizer>(shell.GetTaskRunners());
   };
 
-  if (embedded_views_preview_enabled) {
+  if (shell::IsIosEmbeddedViewsPreviewEnabled()) {
     // Embedded views requires the gpu and the platform views to be the same.
     // The plan is to eventually dynamically merge the threads when there's a
     // platform view in the layer tree.

shell/platform/darwin/ios/ios_surface.h

@@ -15,8 +15,9 @@
 
 namespace shell {
 
-// The name of the Info.plist flag to enable the embedded iOS views preview.
-const char* const kEmbeddedViewsPreview = "io.flutter.embedded_views_preview";
+// Returns true if the app explicitly specified to use the iOS view embedding
+// mechanism which is still in a release preview.
+bool IsIosEmbeddedViewsPreviewEnabled();
 
 class IOSSurface {
  public:

shell/platform/darwin/ios/ios_surface.mm

@@ -11,6 +11,13 @@
 
 namespace shell {
 
+// The name of the Info.plist flag to enable the embedded iOS views preview.
+const char* const kEmbeddedViewsPreview = "io.flutter.embedded_views_preview";
+
+bool IsIosEmbeddedViewsPreviewEnabled() {
+  return [[[NSBundle mainBundle] objectForInfoDictionaryKey:@(kEmbeddedViewsPreview)] boolValue];
+}
+
 IOSSurface::IOSSurface(FlutterPlatformViewsController* platform_views_controller)
     : platform_views_controller_(platform_views_controller) {}
 

shell/platform/darwin/ios/ios_surface_gl.mm

@@ -75,7 +75,7 @@
 }
 
 flow::ExternalViewEmbedder* IOSSurfaceGL::GetExternalViewEmbedder() {
-  if ([[[NSBundle mainBundle] objectForInfoDictionaryKey:@(kEmbeddedViewsPreview)] boolValue]) {
+  if (IsIosEmbeddedViewsPreviewEnabled()) {
     return this;
   } else {
     return nullptr;

shell/platform/darwin/ios/ios_surface_software.mm

@@ -127,7 +127,7 @@
 }
 
 flow::ExternalViewEmbedder* IOSSurfaceSoftware::GetExternalViewEmbedder() {
-  if ([[[NSBundle mainBundle] objectForInfoDictionaryKey:@(kEmbeddedViewsPreview)] boolValue]) {
+  if (IsIosEmbeddedViewsPreviewEnabled()) {
     return this;
   } else {
     return nullptr;