Addressing PR comments.

Renaming variables, created PresentPlatformView method and updated documentation

Author: RichardJCai

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

@@ -58,6 +58,16 @@ - (void)postMainThreadTask:(FlutterTask)task targetTimeInNanoseconds:(uint64_t)t
  */
 - (void)loadAOTData:(NSString*)assetsDir;
 
+/**
+ * Creates and returns a FlutterCompositor* to be used by the embedder.
+ */
+- (FlutterCompositor*)createFlutterCompositor;
+
+/**
+ * Create a platform view channel and setup a method call handler.
+ */
+- (void)setupPlatformViewChannel;
+
 @end
 
 #pragma mark -
@@ -257,7 +267,7 @@ - (BOOL)runWithEntrypoint:(NSString*)entrypoint {
   }
 
   [self setupPlatformViewChannel];
-  [self createPlatformViewController];
+  _platformViewController = [[FlutterPlatformViewController alloc] init];
 
   flutterArguments.compositor = [self createFlutterCompositor];
 
@@ -559,28 +569,24 @@ - (FlutterCompositor*)createFlutterCompositor {
                                                                                layers_count);
   };
 
-  __weak FlutterEngine* weak_self = self;
+  __weak FlutterEngine* weakSelf = self;
   _macOSGLCompositor->SetPresentCallback(
-      [weak_self]() { return [weak_self engineCallbackOnPresent]; });
+      [weakSelf]() { return [weakSelf engineCallbackOnPresent]; });
 
   _compositor.avoid_backing_store_cache = true;
 
   return &_compositor;
 }
 
-- (void)createPlatformViewController {
-  _platformViewController = [[FlutterPlatformViewController alloc] init];
-}
-
 - (void)setupPlatformViewChannel {
   _platformViewsChannel =
       [FlutterMethodChannel methodChannelWithName:@"flutter/platform_views"
                                   binaryMessenger:self.binaryMessenger
                                             codec:[FlutterStandardMethodCodec sharedInstance]];
 
-  __weak FlutterEngine* weak_self = self;
+  __weak FlutterEngine* weakSelf = self;
   [_platformViewsChannel setMethodCallHandler:^(FlutterMethodCall* call, FlutterResult result) {
-    [[weak_self platformViewController] handleMethodCall:call result:result];
+    [[weakSelf platformViewController] handleMethodCall:call result:result];
   }];
 }
 
@@ -690,11 +696,11 @@ - (BOOL)unregisterTextureWithID:(int64_t)textureID {
 - (void)postMainThreadTask:(FlutterTask)task targetTimeInNanoseconds:(uint64_t)targetTime {
   const auto engine_time = _embedderAPI.GetCurrentTime();
 
-  __weak FlutterEngine* weak_self = self;
+  __weak FlutterEngine* weakSelf = self;
   auto worker = ^{
-    FlutterEngine* strong_self = weak_self;
-    if (strong_self && strong_self->_engine) {
-      auto result = _embedderAPI.RunTask(strong_self->_engine, &task);
+    FlutterEngine* strongSelf = weakSelf;
+    if (strongSelf && strongSelf->_engine) {
+      auto result = _embedderAPI.RunTask(strongSelf->_engine, &task);
       if (result != kSuccess) {
         NSLog(@"Could not post a task to the Flutter engine.");
       }

shell/platform/darwin/macos/framework/Source/FlutterGLCompositor.h

@@ -75,6 +75,10 @@ class FlutterGLCompositor {
       FlutterBackingStoreData* flutter_backing_store_data,
       size_t layer_position);
 
+  // Add the Platform View's content to the FlutterView at depth
+  // layer_position.
+  void PresentPlatformView(const FlutterLayer* layer, size_t layer_position);
+
   // Set frame_started_ to true and reset all layer state.
   void StartFrame();
 

shell/platform/darwin/macos/framework/Source/FlutterGLCompositor.mm

@@ -93,23 +93,7 @@
         break;
       }
       case kFlutterLayerContentTypePlatformView:
-        FML_DCHECK([[NSThread currentThread] isMainThread])
-            << "Must be on the main thread to handle presenting platform views";
-
-        FML_DCHECK(platform_view_controller_.platformViews.count(layer->platform_view->identifier))
-            << "Platform view not found for id: " << layer->platform_view->identifier;
-
-        NSView* platform_view =
-            platform_view_controller_.platformViews[layer->platform_view->identifier];
-
-        CGFloat scale = [[NSScreen mainScreen] backingScaleFactor];
-        platform_view.frame = CGRectMake(layer->offset.x / scale, layer->offset.y / scale,
-                                         layer->size.width / scale, layer->size.height / scale);
-        if (platform_view.superview == nil) {
-          [view_controller_.flutterView addSubview:platform_view];
-        } else {
-          platform_view.layer.zPosition = i;
-        }
+        PresentPlatformView(layer, i);
         break;
     };
   }
@@ -142,6 +126,25 @@
   [content_layer setContents:(__bridge id)io_surface_contents];
 }
 
+void FlutterGLCompositor::PresentPlatformView(const FlutterLayer* layer, size_t layer_position) {
+  FML_DCHECK([[NSThread currentThread] isMainThread])
+      << "Must be on the main thread to handle presenting platform views";
+
+  FML_DCHECK(platform_view_controller_.platformViews.count(layer->platform_view->identifier))
+      << "Platform view not found for id: " << layer->platform_view->identifier;
+
+  NSView* platform_view = platform_view_controller_.platformViews[layer->platform_view->identifier];
+
+  CGFloat scale = [[NSScreen mainScreen] backingScaleFactor];
+  platform_view.frame = CGRectMake(layer->offset.x / scale, layer->offset.y / scale,
+                                   layer->size.width / scale, layer->size.height / scale);
+  if (platform_view.superview == nil) {
+    [view_controller_.flutterView addSubview:platform_view];
+  } else {
+    platform_view.layer.zPosition = layer_position;
+  }
+}
+
 void FlutterGLCompositor::SetPresentCallback(
     const FlutterGLCompositor::PresentCallback& present_callback) {
   present_callback_ = present_callback;

shell/platform/darwin/macos/framework/Source/FlutterPlatformViewController.mm

@@ -10,8 +10,9 @@ @implementation FlutterPlatformViewController
 
 - (instancetype)init {
   self = [super init];
-
-  self->_platformViewFactories = [[NSMutableDictionary alloc] init];
+  if (self) {
+    _platformViewFactories = [[NSMutableDictionary alloc] init];
+  }
   return self;
 }
 

shell/platform/darwin/macos/framework/Source/FlutterPlatformViewMock.h

@@ -3,7 +3,6 @@
 // found in the LICENSE file.
 
 #import <Foundation/Foundation.h>
-#import <Foundation/NSObject.h>
 
 #import "flutter/shell/platform/darwin/macos/framework/Source/FlutterPlatformViews.h"