embedder: merge embedder.h from flutter/engine (#416)

Merged from https://github.com/flutter/engine/commits/3.22.0/shell/platform/embedder/embedder.h

Signed-off-by: Hidenori Matsubayashi <Hidenori.Matsubayashi@gmail.com>

src/flutter/shell/platform/embedder/embedder.h

@@ -831,6 +831,53 @@ typedef struct {
   };
 } FlutterRendererConfig;
 
+typedef struct {
+  /// The size of this struct.
+  /// Must be sizeof(FlutterRemoveViewResult).
+  size_t struct_size;
+
+  /// True if the remove view operation succeeded.
+  bool removed;
+
+  /// The |FlutterRemoveViewInfo.user_data|.
+  void* user_data;
+} FlutterRemoveViewResult;
+
+/// The callback invoked by the engine when the engine has attempted to remove
+/// a view.
+///
+/// The |FlutterRemoveViewResult| will be deallocated once the callback returns.
+typedef void (*FlutterRemoveViewCallback)(
+    const FlutterRemoveViewResult* /* result */);
+
+typedef struct {
+  /// The size of this struct.
+  /// Must be sizeof(FlutterRemoveViewInfo).
+  size_t struct_size;
+
+  /// The identifier for the view to remove.
+  ///
+  /// The implicit view cannot be removed if it is enabled.
+  FlutterViewId view_id;
+
+  /// A baton that is not interpreted by the engine in any way.
+  /// It will be given back to the embedder in |remove_view_callback|.
+  /// Embedder resources may be associated with this baton.
+  void* user_data;
+
+  /// Called once the engine has attempted to remove the view.
+  /// This callback is required.
+  ///
+  /// The embedder must not destroy the underlying surface until the callback is
+  /// invoked with a `removed` value of `true`.
+  ///
+  /// This callback is invoked on an internal engine managed thread.
+  /// Embedders must re-thread if necessary.
+  ///
+  /// The |result| argument will be deallocated when the callback returns.
+  FlutterRemoveViewCallback remove_view_callback;
+} FlutterRemoveViewInfo;
+
 /// Display refers to a graphics hardware system consisting of a framebuffer,
 /// typically a monitor or a screen. This ID is unique per display and is
 /// stable until the Flutter application restarts.
@@ -859,6 +906,8 @@ typedef struct {
   double physical_view_inset_left;
   /// The identifier of the display the view is rendering on.
   FlutterEngineDisplayId display_id;
+  /// The view that this event is describing.
+  int64_t view_id;
 } FlutterWindowMetricsEvent;
 
 /// The phase of the pointer event.
@@ -1736,8 +1785,30 @@ typedef struct {
   /// Extra information for the backing store that the embedder may
   /// use during presentation.
   FlutterBackingStorePresentInfo* backing_store_present_info;
+
+  // Time in nanoseconds at which this frame is scheduled to be presented. 0 if
+  // not known. See FlutterEngineGetCurrentTime().
+  uint64_t presentation_time;
 } FlutterLayer;
 
+typedef struct {
+  /// The size of this struct.
+  /// Must be sizeof(FlutterPresentViewInfo).
+  size_t struct_size;
+
+  /// The identifier of the target view.
+  FlutterViewId view_id;
+
+  /// The layers that should be composited onto the view.
+  const FlutterLayer** layers;
+
+  /// The count of layers.
+  size_t layers_count;
+
+  /// The |FlutterCompositor.user_data|.
+  void* user_data;
+} FlutterPresentViewInfo;
+
 typedef bool (*FlutterBackingStoreCreateCallback)(
     const FlutterBackingStoreConfig* config,
     FlutterBackingStore* backing_store_out,
@@ -1751,13 +1822,20 @@ typedef bool (*FlutterLayersPresentCallback)(const FlutterLayer** layers,
                                              size_t layers_count,
                                              void* user_data);
 
+/// The callback invoked when the embedder should present to a view.
+///
+/// The |FlutterPresentViewInfo| will be deallocated once the callback returns.
+typedef bool (*FlutterPresentViewCallback)(
+    const FlutterPresentViewInfo* /* present info */);
+
 typedef struct {
   /// This size of this struct. Must be sizeof(FlutterCompositor).
   size_t struct_size;
   /// A baton that in not interpreted by the engine in any way. If it passed
   /// back to the embedder in `FlutterCompositor.create_backing_store_callback`,
-  /// `FlutterCompositor.collect_backing_store_callback` and
-  /// `FlutterCompositor.present_layers_callback`
+  /// `FlutterCompositor.collect_backing_store_callback`,
+  /// `FlutterCompositor.present_layers_callback`, and
+  /// `FlutterCompositor.present_view_callback`.
   void* user_data;
   /// A callback invoked by the engine to obtain a backing store for a specific
   /// `FlutterLayer`.
@@ -1771,10 +1849,23 @@ typedef struct {
   /// embedder may collect any resources associated with the backing store.
   FlutterBackingStoreCollectCallback collect_backing_store_callback;
   /// Callback invoked by the engine to composite the contents of each layer
-  /// onto the screen.
+  /// onto the implicit view.
+  ///
+  /// DEPRECATED: Use |present_view_callback| to support multiple views.
+  ///
+  /// Only one of `present_layers_callback` and `present_view_callback` may be
+  /// provided. Providing both is an error and engine initialization will
+  /// terminate.
   FlutterLayersPresentCallback present_layers_callback;
   /// Avoid caching backing stores provided by this compositor.
   bool avoid_backing_store_cache;
+  /// Callback invoked by the engine to composite the contents of each layer
+  /// onto the specified view.
+  ///
+  /// Only one of `present_layers_callback` and `present_view_callback` may be
+  /// provided. Providing both is an error and engine initialization will
+  /// terminate.
+  FlutterPresentViewCallback present_view_callback;
 } FlutterCompositor;
 
 typedef struct {
@@ -2414,6 +2505,25 @@ FLUTTER_EXPORT
 FlutterEngineResult FlutterEngineRunInitialized(
     FLUTTER_API_SYMBOL(FlutterEngine) engine);
 
+//------------------------------------------------------------------------------
+/// @brief      Removes a view.
+///
+///             This is an asynchronous operation. The view's resources must not
+///             be cleaned up until the |remove_view_callback| is invoked with
+///             a |removed| value of `true`.
+///
+/// @param[in]  engine  A running engine instance.
+/// @param[in]  info    The remove view arguments. This can be deallocated
+///                     once |FlutterEngineRemoveView| returns, before
+///                     |remove_view_callback| is invoked.
+///
+/// @return     The result of *starting* the asynchronous operation. If
+///             `kSuccess`, the |remove_view_callback| will be invoked.
+FLUTTER_EXPORT
+FlutterEngineResult FlutterEngineRemoveView(FLUTTER_API_SYMBOL(FlutterEngine)
+                                                engine,
+                                            const FlutterRemoveViewInfo* info);
+
 FLUTTER_EXPORT
 FlutterEngineResult FlutterEngineSendWindowMetricsEvent(
     FLUTTER_API_SYMBOL(FlutterEngine) engine,