header gueards

Author: knopp

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

@@ -1,3 +1,6 @@
+#ifndef FLUTTER_SHELL_PLATFORM_DARWIN_MACOS_FRAMEWORK_SOURCE_FLUTTERDISPLAYLINK_H_
+#define FLUTTER_SHELL_PLATFORM_DARWIN_MACOS_FRAMEWORK_SOURCE_FLUTTERDISPLAYLINK_H_
+
 #import <AppKit/AppKit.h>
 
 @protocol FlutterDisplayLinkDelegate <NSObject>
@@ -33,3 +36,5 @@
 - (void)invalidate;
 
 @end
+
+#endif  // FLUTTER_SHELL_PLATFORM_DARWIN_MACOS_FRAMEWORK_SOURCE_FLUTTERDISPLAYLINK_H_

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

@@ -1,3 +1,6 @@
+#ifndef FLUTTER_SHELL_PLATFORM_DARWIN_MACOS_FRAMEWORK_SOURCE_FLUTTERVSYNCWAITER_H_
+#define FLUTTER_SHELL_PLATFORM_DARWIN_MACOS_FRAMEWORK_SOURCE_FLUTTERVSYNCWAITER_H_
+
 #import <AppKit/AppKit.h>
 
 @class FlutterDisplayLink;
@@ -19,3 +22,5 @@
 - (void)waitForVSync:(uintptr_t)baton;
 
 @end
+
+#endif  // FLUTTER_SHELL_PLATFORM_DARWIN_MACOS_FRAMEWORK_SOURCE_FLUTTERVSYNCWAITER_H_