Make FLEViewController's view an internal detail (#9741)

Rather than clients needing to create an appropriate view in a XIB and
attach it to an FLEViewController, which is error-prone, have
FLEViewController create its own view programatically. The view is now
an internal detail, so calling setView: on an FLEViewController will no
longer work.

As a result of the view being internal, the public API surface is
simplified.

This is a breaking change for macOS Runners.

ci/licenses_golden/licenses_flutter

@@ -750,9 +750,6 @@ FILE: ../../../flutter/shell/platform/darwin/ios/platform_view_ios.mm
 FILE: ../../../flutter/shell/platform/darwin/macos/framework/FlutterMacOS.podspec
 FILE: ../../../flutter/shell/platform/darwin/macos/framework/Headers/FLEDartProject.h
 FILE: ../../../flutter/shell/platform/darwin/macos/framework/Headers/FLEEngine.h
-FILE: ../../../flutter/shell/platform/darwin/macos/framework/Headers/FLEOpenGLContextHandling.h
-FILE: ../../../flutter/shell/platform/darwin/macos/framework/Headers/FLEReshapeListener.h
-FILE: ../../../flutter/shell/platform/darwin/macos/framework/Headers/FLEView.h
 FILE: ../../../flutter/shell/platform/darwin/macos/framework/Headers/FLEViewController.h
 FILE: ../../../flutter/shell/platform/darwin/macos/framework/Headers/FlutterMacOS.h
 FILE: ../../../flutter/shell/platform/darwin/macos/framework/Headers/FlutterPluginMacOS.h
@@ -766,9 +763,10 @@ FILE: ../../../flutter/shell/platform/darwin/macos/framework/Source/FLETextInput
 FILE: ../../../flutter/shell/platform/darwin/macos/framework/Source/FLETextInputModel.mm
 FILE: ../../../flutter/shell/platform/darwin/macos/framework/Source/FLETextInputPlugin.h
 FILE: ../../../flutter/shell/platform/darwin/macos/framework/Source/FLETextInputPlugin.mm
-FILE: ../../../flutter/shell/platform/darwin/macos/framework/Source/FLEView.mm
 FILE: ../../../flutter/shell/platform/darwin/macos/framework/Source/FLEViewController.mm
 FILE: ../../../flutter/shell/platform/darwin/macos/framework/Source/FLEViewController_Internal.h
+FILE: ../../../flutter/shell/platform/darwin/macos/framework/Source/FlutterView.h
+FILE: ../../../flutter/shell/platform/darwin/macos/framework/Source/FlutterView.mm
 FILE: ../../../flutter/shell/platform/darwin/macos/framework/module.modulemap
 FILE: ../../../flutter/shell/platform/embedder/assets/EmbedderInfo.plist
 FILE: ../../../flutter/shell/platform/embedder/assets/embedder.modulemap

shell/platform/darwin/macos/BUILD.gn

@@ -35,9 +35,6 @@ _flutter_framework_headers = [
   "framework/Headers/FlutterPluginRegistrarMacOS.h",
   "framework/Headers/FLEDartProject.h",
   "framework/Headers/FLEEngine.h",
-  "framework/Headers/FLEOpenGLContextHandling.h",
-  "framework/Headers/FLEReshapeListener.h",
-  "framework/Headers/FLEView.h",
   "framework/Headers/FLEViewController.h",
 ]
 
@@ -58,9 +55,10 @@ shared_library("create_flutter_framework_dylib") {
     "framework/Source/FLETextInputModel.mm",
     "framework/Source/FLETextInputPlugin.h",
     "framework/Source/FLETextInputPlugin.mm",
-    "framework/Source/FLEView.mm",
     "framework/Source/FLEViewController.mm",
     "framework/Source/FLEViewController_Internal.h",
+    "framework/Source/FlutterView.h",
+    "framework/Source/FlutterView.mm",
   ]
 
   sources += _flutter_framework_headers

shell/platform/darwin/macos/framework/Headers/FLEOpenGLContextHandling.h

-// Copyright 2013 The Flutter Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-#import "FlutterMacros.h"
-
-/**
- * Protocol for views owned by FLEViewController to handle context changes, specifically relating to
- * OpenGL context changes.
- */
-FLUTTER_EXPORT
-@protocol FLEOpenGLContextHandling
-
-/**
- * Sets the receiver as the current context object.
- */
-- (void)makeCurrentContext;
-
-/**
- * Called when the display is updated. In an NSOpenGLView this is best handled via a flushBuffer
- * call.
- */
-- (void)onPresent;
-
-@end

shell/platform/darwin/macos/framework/Headers/FLEReshapeListener.h

-// Copyright 2013 The Flutter Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-#import <Cocoa/Cocoa.h>
-
-#import "FlutterMacros.h"
-
-/**
- * Protocol for listening to reshape events on this FlutterView.
- * Used to notify the underlying Flutter engine of the new screen dimensions.
- * Reflected from [NSOpenGLView.reshape].
- */
-FLUTTER_EXPORT
-@protocol FLEReshapeListener
-
-- (void)viewDidReshape:(nonnull NSOpenGLView*)view;
-
-@end

shell/platform/darwin/macos/framework/Headers/FLEView.h

-// Copyright 2013 The Flutter Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-#import <Cocoa/Cocoa.h>
-
-#import "FLEOpenGLContextHandling.h"
-#import "FLEReshapeListener.h"
-#import "FlutterMacros.h"
-
-/**
- * View capable of acting as a rendering target and input source for the Flutter
- * engine.
- */
-FLUTTER_EXPORT
-@interface FLEView : NSOpenGLView <FLEOpenGLContextHandling>
-
-/**
- * Listener for reshape events. See protocol description.
- */
-@property(nonatomic, weak, nullable) IBOutlet id<FLEReshapeListener> reshapeListener;
-
-@end

shell/platform/darwin/macos/framework/Headers/FLEViewController.h

@@ -5,8 +5,6 @@
 #import <Cocoa/Cocoa.h>
 
 #import "FLEEngine.h"
-#import "FLEOpenGLContextHandling.h"
-#import "FLEReshapeListener.h"
 #import "FlutterMacros.h"
 #import "FlutterPluginRegistrarMacOS.h"
 
@@ -29,13 +27,7 @@ typedef NS_ENUM(NSInteger, FlutterMouseTrackingMode) {
  * Flutter engine in non-interactive mode, or with a drawable Flutter canvas.
  */
 FLUTTER_EXPORT
-@interface FLEViewController : NSViewController <FlutterPluginRegistry, FLEReshapeListener>
-
-/**
- * The view this controller manages. Must be capable of handling text input events, and the OpenGL
- * context handling protocols.
- */
-@property(nullable) NSView<FLEOpenGLContextHandling>* view;
+@interface FLEViewController : NSViewController <FlutterPluginRegistry>
 
 /**
  * The Flutter engine associated with this view controller.

shell/platform/darwin/macos/framework/Headers/FlutterMacOS.h

@@ -4,9 +4,6 @@
 
 #import "FLEDartProject.h"
 #import "FLEEngine.h"
-#import "FLEOpenGLContextHandling.h"
-#import "FLEReshapeListener.h"
-#import "FLEView.h"
 #import "FLEViewController.h"
 #import "FlutterBinaryMessenger.h"
 #import "FlutterChannels.h"

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

@@ -210,15 +210,15 @@ static void OnPlatformMessage(const FlutterPlatformMessage* message, FLEEngine*
 #pragma mark - Private methods
 
 - (bool)engineCallbackOnMakeCurrent {
-  if (!_viewController.view) {
+  if (!_viewController.flutterView) {
     return false;
   }
-  [_viewController.view makeCurrentContext];
+  [_viewController.flutterView makeCurrentContext];
   return true;
 }
 
 - (bool)engineCallbackOnClearCurrent {
-  if (!_viewController.view) {
+  if (!_viewController.flutterView) {
     return false;
   }
   [NSOpenGLContext clearCurrentContext];
@@ -226,15 +226,15 @@ static void OnPlatformMessage(const FlutterPlatformMessage* message, FLEEngine*
 }
 
 - (bool)engineCallbackOnPresent {
-  if (!_viewController.view) {
+  if (!_viewController.flutterView) {
     return false;
   }
-  [_viewController.view onPresent];
+  [_viewController.flutterView onPresent];
   return true;
 }
 
 - (bool)engineCallbackOnMakeResourceCurrent {
-  if (!_viewController.view) {
+  if (!_viewController.flutterView) {
     return false;
   }
   [_viewController makeResourceContextCurrent];

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

@@ -8,10 +8,9 @@
 #import "flutter/shell/platform/darwin/common/framework/Headers/FlutterChannels.h"
 #import "flutter/shell/platform/darwin/common/framework/Headers/FlutterCodecs.h"
 #import "flutter/shell/platform/darwin/macos/framework/Headers/FLEEngine.h"
-#import "flutter/shell/platform/darwin/macos/framework/Headers/FLEReshapeListener.h"
-#import "flutter/shell/platform/darwin/macos/framework/Headers/FLEView.h"
 #import "flutter/shell/platform/darwin/macos/framework/Source/FLEEngine_Internal.h"
 #import "flutter/shell/platform/darwin/macos/framework/Source/FLETextInputPlugin.h"
+#import "flutter/shell/platform/darwin/macos/framework/Source/FlutterView.h"
 #import "flutter/shell/platform/embedder/embedder.h"
 
 namespace {
@@ -68,7 +67,7 @@ struct MouseState {
 /**
  * Private interface declaration for FLEViewController.
  */
-@interface FLEViewController ()
+@interface FLEViewController () <FlutterViewReshapeListener>
 
 /**
  * A list of additional responders to keyboard events. Keybord events are forwarded to all of them.
@@ -195,16 +194,13 @@ static void CommonInit(FLEViewController* controller) {
   return self;
 }
 
-- (void)setView:(NSView*)view {
-  if (_trackingArea) {
-    [self.view removeTrackingArea:_trackingArea];
-  }
-  [super setView:view];
-  [self configureTrackingArea];
+- (void)loadView {
+  FlutterView* flutterView = [[FlutterView alloc] initWithReshapeListener:self];
+  self.view = flutterView;
 }
 
-- (void)loadView {
-  self.view = [[FLEView alloc] init];
+- (void)viewDidLoad {
+  [self configureTrackingArea];
 }
 
 #pragma mark - Public methods
@@ -238,6 +234,10 @@ static void CommonInit(FLEViewController* controller) {
 
 #pragma mark - Framework-internal methods
 
+- (FlutterView*)flutterView {
+  return static_cast<FlutterView*>(self.view);
+}
+
 - (void)addKeyResponder:(NSResponder*)responder {
   [self.additionalKeyResponders addObject:responder];
 }
@@ -449,12 +449,12 @@ static void CommonInit(FLEViewController* controller) {
   }
 }
 
-#pragma mark - FLEReshapeListener
+#pragma mark - FlutterViewReshapeListener
 
 /**
  * Responds to view reshape by notifying the engine of the change in dimensions.
  */
-- (void)viewDidReshape:(NSOpenGLView*)view {
+- (void)viewDidReshape:(NSView*)view {
   CGSize scaledSize = [view convertRectToBacking:view.bounds].size;
   double pixelRatio = view.bounds.size.width == 0 ? 1 : scaledSize.width / view.bounds.size.width;
   [_engine updateWindowMetricsWithSize:scaledSize pixelRatio:pixelRatio];

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

@@ -4,8 +4,13 @@
 
 #import "flutter/shell/platform/darwin/macos/framework/Headers/FLEViewController.h"
 
+#import "flutter/shell/platform/darwin/macos/framework/Source/FlutterView.h"
+
 @interface FLEViewController ()
 
+// The FlutterView for this view controller.
+@property(nonatomic, readonly, nullable) FlutterView* flutterView;
+
 /**
  * Adds a responder for keyboard events. Key up and key down events are forwarded to all added
  * responders.

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

+// Copyright 2013 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#import <Cocoa/Cocoa.h>
+
+/**
+ * Listener for view resizing.
+ */
+@protocol FlutterViewReshapeListener <NSObject>
+/**
+ * Called when the view's backing store changes size.
+ */
+- (void)viewDidReshape:(nonnull NSView*)view;
+@end
+
+/**
+ * View capable of acting as a rendering target and input source for the Flutter
+ * engine.
+ */
+@interface FlutterView : NSOpenGLView
+
+- (nullable instancetype)initWithFrame:(NSRect)frame
+                       reshapeListener:(nonnull id<FlutterViewReshapeListener>)reshapeListener
+    NS_DESIGNATED_INITIALIZER;
+
+- (nullable instancetype)initWithReshapeListener:
+    (nonnull id<FlutterViewReshapeListener>)reshapeListener;
+
+- (nullable instancetype)initWithFrame:(NSRect)frameRect
+                           pixelFormat:(nullable NSOpenGLPixelFormat*)format NS_UNAVAILABLE;
+- (nonnull instancetype)initWithFrame:(NSRect)frameRect NS_UNAVAILABLE;
+- (nullable instancetype)initWithCoder:(nonnull NSCoder*)coder NS_UNAVAILABLE;
+- (nonnull instancetype)init NS_UNAVAILABLE;
+
+/**
+ * Sets this view as the current context object for OpenGL drawing.
+ */
+- (void)makeCurrentContext;
+
+/**
+ * Called when the OpenGL display should be updated.
+ */
+- (void)onPresent;
+
+@end

shell/platform/darwin/macos/framework/Source/FLEView.mm → shell/platform/darwin/macos/framework/Source/FlutterView.mm

@@ -2,12 +2,29 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#import "flutter/shell/platform/darwin/macos/framework/Headers/FLEView.h"
+#import "flutter/shell/platform/darwin/macos/framework/Source/FlutterView.h"
 
-@implementation FLEView
+@implementation FlutterView {
+  __weak id<FlutterViewReshapeListener> _reshapeListener;
+}
+
+- (instancetype)initWithReshapeListener:(id<FlutterViewReshapeListener>)reshapeListener {
+  return [self initWithFrame:NSZeroRect reshapeListener:reshapeListener];
+}
 
-#pragma mark -
-#pragma mark FLEContextHandlingProtocol
+- (instancetype)initWithFrame:(NSRect)frame
+              reshapeListener:(id<FlutterViewReshapeListener>)reshapeListener {
+  NSOpenGLPixelFormatAttribute attributes[] = {
+      NSOpenGLPFAColorSize, 24, NSOpenGLPFAAlphaSize, 8, NSOpenGLPFADoubleBuffer, 0,
+  };
+  NSOpenGLPixelFormat* pixelFormat = [[NSOpenGLPixelFormat alloc] initWithAttributes:attributes];
+  self = [super initWithFrame:frame pixelFormat:pixelFormat];
+  if (self) {
+    _reshapeListener = reshapeListener;
+    self.wantsBestResolutionOpenGLSurface = YES;
+  }
+  return self;
+}
 
 - (void)makeCurrentContext {
   [self.openGLContext makeCurrentContext];
@@ -17,8 +34,7 @@
   [self.openGLContext flushBuffer];
 }
 
-#pragma mark -
-#pragma mark Implementation
+#pragma mark - NSView overrides
 
 /**
  * Declares that the view uses a flipped coordinate system, consistent with Flutter conventions.