Remove log, fix doc

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

@@ -252,6 +252,8 @@ @implementation FlutterEngine {
   std::unique_ptr<flutter::FlutterCompositor> _macOSCompositor;
 
   // The information of all views attached to this engine mapped from IDs.
+  //
+  // It can't use NSDictionary, because the values need to be weak references.
   NSMapTable* _viewControllers;
 
   // FlutterCompositor is copied and used in embedder.cc.

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

@@ -651,8 +651,9 @@ - (nonnull NSView*)createWithViewIdentifier:(int64_t)viewId arguments:(nullable
 }
 
 TEST_F(FlutterEngineTest, ManageControllersIfInitiatedByEngine) {
-  // Don't create the engine with `CreateMockFlutterEngine` because the latter
-  // introduces memory leakage.
+  // Don't create the engine with `CreateMockFlutterEngine`, because it adds
+  // additional references to FlutterViewControllers, which is crucial to this
+  // test case.
   FlutterEngine* engine = [[FlutterEngine alloc] initWithName:@"io.flutter"
                                                       project:nil
                                        allowHeadlessExecution:NO];

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

@@ -99,20 +99,16 @@ - (FlutterMetalTexture)createTextureForView:(uint64_t)viewId size:(CGSize)size {
 }
 
 - (BOOL)present:(uint64_t)viewId texture:(const FlutterMetalTexture*)texture {
-  NSLog(@"Present %llu", viewId);
   FlutterView* view = [_viewProvider getViewForId:viewId];
-  NSLog(@"Present View %@", view);
   if (view == nil) {
     return NO;
   }
   FlutterSurface* surface = [FlutterSurface fromFlutterMetalTexture:texture];
-  NSLog(@"Present surface %@", surface);
   if (surface == nil) {
     return NO;
   }
   FlutterSurfacePresentInfo* info = [[FlutterSurfacePresentInfo alloc] init];
   info.surface = surface;
-  NSLog(@"Present surfaceMgr %@", view.surfaceManager);
   [view.surfaceManager present:@[ info ] notify:nil];
   return YES;
 }