Remove unneeded Mac SDK forward declaration.

BUG=1044828

Change-Id: I375866984e4878833b19c29a1276af948756b228
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2016860
Commit-Queue: Elly Fong-Jones <ellyjones@chromium.org>
Auto-Submit: Avi Drissman <avi@chromium.org>
Reviewed-by: Elly Fong-Jones <ellyjones@chromium.org>
Cr-Commit-Position: refs/heads/master@{#734665}

base/mac/sdk_forward_declarations.h

@@ -155,27 +155,6 @@ typedef NSString* VNBarcodeSymbology NS_STRING_ENUM;
 
 #endif  // MAC_OS_X_VERSION_10_13
 
-// Once Chrome no longer supports macOS 10.13, everything within this
-// preprocessor block can be removed.
-#if !defined(MAC_OS_X_VERSION_10_14) || \
-    MAC_OS_X_VERSION_MIN_REQUIRED < MAC_OS_X_VERSION_10_14
-
-typedef NSString* NSAppearanceName;
-
-@interface NSApplication (ForwardDeclare)
-@property(strong) NSAppearance* appearance;
-@property(readonly, strong) NSAppearance* effectiveAppearance;
-@end
-
-@interface NSAppearance (ForwardDeclare)
-- (NSAppearanceName)bestMatchFromAppearancesWithNames:
-    (NSArray<NSAppearanceName>*)appearances;
-@end
-
-BASE_EXPORT extern NSAppearanceName const NSAppearanceNameDarkAqua;
-
-#endif  // MAC_OS_X_VERSION_10_14
-
 #if !defined(MAC_OS_X_VERSION_10_15) || \
     MAC_OS_X_VERSION_MIN_REQUIRED < MAC_OS_X_VERSION_10_15
 

base/mac/sdk_forward_declarations.mm

@@ -8,8 +8,3 @@
     MAC_OS_X_VERSION_MIN_REQUIRED < MAC_OS_X_VERSION_10_11
 NSString* const CIDetectorTypeText = @"CIDetectorTypeText";
 #endif  // MAC_OS_X_VERSION_10_11
-
-#if !defined(MAC_OS_X_VERSION_10_14) || \
-    MAC_OS_X_VERSION_MIN_REQUIRED < MAC_OS_X_VERSION_10_14
-NSString* const NSAppearanceNameDarkAqua = @"NSAppearanceNameDarkAqua";
-#endif