[macOS] Eliminate mirrors support

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

@@ -29,13 +29,6 @@ FLUTTER_DARWIN_EXPORT
 - (nonnull instancetype)initWithPrecompiledDartBundle:(nullable NSBundle*)bundle
     NS_DESIGNATED_INITIALIZER;
 
-/**
- * If set, allows the Flutter project to use the dart:mirrors library.
- *
- * Deprecated: This function is temporary and will be removed in a future release.
- */
-@property(nonatomic) bool enableMirrors;
-
 /**
  * An NSArray of NSStrings to be passed as command line arguments to the Dart entrypoint.
  *

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

@@ -81,12 +81,4 @@ - (NSString*)ICUDataPath {
   return path;
 }
 
-- (std::vector<std::string>)switches {
-  std::vector<std::string> arguments = flutter::GetSwitchesFromEnvironment();
-  if (self.enableMirrors) {
-    arguments.push_back("--dart-flags=--enable_mirrors=true");
-  }
-  return arguments;
-}
-
 @end

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

@@ -25,11 +25,6 @@
  */
 @property(nonatomic, readonly, nullable) NSString* ICUDataPath;
 
-/**
- * The command line arguments array for the engine.
- */
-@property(nonatomic, readonly) std::vector<std::string> switches;
-
 /**
  * The callback invoked by the engine in root isolate scope.
  */

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

@@ -9,6 +9,7 @@
 #include <iostream>
 #include <vector>
 
+#include "flutter/shell/platform/common/engine_switches.h"
 #import "flutter/shell/platform/darwin/macos/framework/Source/FlutterCompositor.h"
 #import "flutter/shell/platform/darwin/macos/framework/Source/FlutterDartProject_Internal.h"
 #import "flutter/shell/platform/darwin/macos/framework/Source/FlutterMenuPlugin.h"
@@ -337,7 +338,7 @@ - (BOOL)runWithEntrypoint:(NSString*)entrypoint {
 
   // The first argument of argv is required to be the executable name.
   std::vector<const char*> argv = {[self.executableName UTF8String]};
-  std::vector<std::string> switches = _project.switches;
+  std::vector<std::string> switches = self.switches;
   std::transform(switches.begin(), switches.end(), std::back_inserter(argv),
                  [](const std::string& arg) -> const char* { return arg.c_str(); });
 
@@ -917,6 +918,10 @@ - (NSPasteboard*)pasteboard {
   return [NSPasteboard generalPasteboard];
 }
 
+- (std::vector<std::string>)switches {
+  return flutter::GetSwitchesFromEnvironment();
+}
+
 #pragma mark - FlutterBinaryMessenger
 
 - (void)sendOnChannel:(nonnull NSString*)channel message:(nullable NSData*)message {

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

@@ -69,6 +69,24 @@ - (nonnull NSView*)createWithViewIdentifier:(int64_t)viewId arguments:(nullable
   latch.Wait();
 }
 
+#ifndef FLUTTER_RELEASE
+TEST_F(FlutterEngineTest, Switches) {
+  setenv("FLUTTER_ENGINE_SWITCHES", "2", 1);
+  setenv("FLUTTER_ENGINE_SWITCH_1", "abc", 1);
+  setenv("FLUTTER_ENGINE_SWITCH_2", "foo=\"bar, baz\"", 1);
+
+  FlutterEngine* engine = GetFlutterEngine();
+  std::vector<std::string> switches = engine.switches;
+  ASSERT_EQ(switches.size(), 2UL);
+  EXPECT_EQ(switches[0], "--abc");
+  EXPECT_EQ(switches[1], "--foo=\"bar, baz\"");
+
+  unsetenv("FLUTTER_ENGINE_SWITCHES");
+  unsetenv("FLUTTER_ENGINE_SWITCH_1");
+  unsetenv("FLUTTER_ENGINE_SWITCH_2");
+}
+#endif  // !FLUTTER_RELEASE
+
 TEST_F(FlutterEngineTest, MessengerSend) {
   FlutterEngine* engine = GetFlutterEngine();
   EXPECT_TRUE([engine runWithEntrypoint:@"main"]);

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

@@ -47,6 +47,11 @@
  */
 @property(nonatomic, readonly, nonnull) NSPasteboard* pasteboard;
 
+/**
+ * The command line arguments array for the engine.
+ */
+@property(nonatomic, readonly) std::vector<std::string> switches;
+
 /**
  * Attach a view controller to the engine as its default controller.
  *