Enable "Hide Extension" option when "Save Link As" on the Mac

content/browser/download/file_metadata_mac.mm

Index: content/browser/download/file_metadata_mac.mm
diff --git a/content/browser/download/file_metadata_mac.mm b/content/browser/download/file_metadata_mac.mm
index f4ae3c9750943adc0b88b14dfeafde35f09be680..02bb755444bd609be69543c440467b313de40379 100644
--- a/content/browser/download/file_metadata_mac.mm
+++ b/content/browser/download/file_metadata_mac.mm
@@ -166,4 +166,18 @@ void AddQuarantineMetadataToFile(const base::FilePath& file, const GURL& source,
   }
 }
 
+void SetExtensionHiddenForFile(const base::FilePath& file, bool hidden) {
+  NSString* filePath =
+      [NSString stringWithUTF8String:file.value().c_str()];
+  if (filePath) {
+    NSNumber* boolNumber = [NSNumber numberWithBool:hidden ? YES : NO];

[Avi (use Gerrit), 2015/12/12 00:41:46]

bool ? YES : NO is not useful; bools convert as 1 and 0, which are YES and NO.

Couldn't you just do "@(hidden)" below?

[shrike, 2015/12/16 19:04:12]

Acknowledged.

+    NSDictionary* attributes =
+        [NSDictionary dictionaryWithObject:boolNumber
+                                    forKey:NSFileExtensionHidden];

[Avi (use Gerrit), 2015/12/12 00:41:46]

NSDictionary* attributes = @{ NSFileExtensionHidden : @(hidden) };

should work.

[shrike, 2015/12/16 19:04:12]

Done.

+    [[NSFileManager defaultManager] setAttributes:attributes
+                                     ofItemAtPath:filePath
+                                            error:nullptr];
+  }
+}
+
 }  // namespace content