Small fixes

examples/glfw/FlutterEmbedderGLFW.cc

@@ -13,7 +13,7 @@
 static double g_pixelRatio = 1.0;
 static const size_t kInitialWindowWidth = 800;
 static const size_t kInitialWindowHeight = 600;
-static constexpr int64_t kImplicitViewId = 0;
+static constexpr FlutterViewId kImplicitViewId = 0;
 
 static_assert(FLUTTER_ENGINE_VERSION == 1,
               "This Flutter Embedder was authored against the stable Flutter "

examples/glfw_drm/FlutterEmbedderGLFW.cc

@@ -26,7 +26,7 @@ static const size_t kInitialWindowHeight = 600;
 // Maximum damage history - for triple buffering we need to store damage for
 // last two frames; Some Android devices (Pixel 4) use quad buffering.
 static const int kMaxHistorySize = 10;
-static constexpr int64_t kImplicitViewId = 0;
+static constexpr FlutterViewId kImplicitViewId = 0;
 
 // Keeps track of the most recent frame damages so that existing damage can
 // be easily computed.

shell/platform/embedder/embedder.h

@@ -266,6 +266,15 @@ typedef enum {
 
 typedef struct _FlutterEngine* FLUTTER_API_SYMBOL(FlutterEngine);
 
+/// Identifier for views.
+///
+/// How view IDs are generated is decided by the embedding. The engine does not
+/// assume any specifics about the generation algorithm, including whether it
+/// utilizes the entire range of int64_t or permits the use of zero or negative
+/// IDs. The only requirement is that at any given moment, no two views share
+/// the same ID.
+typedef int64_t FlutterViewId;
+
 typedef struct {
   /// horizontal scale factor
   double scaleX;