Be explicit about target type in platform_util::OpenItem()

chrome/browser/platform_util.h

Index: chrome/browser/platform_util.h
diff --git a/chrome/browser/platform_util.h b/chrome/browser/platform_util.h
index 916f3a307c78cb99af4dae2f82191483985a8475..bc4fa4aac921d1f580cfe5f8c2b0fb43ff36a013 100644
--- a/chrome/browser/platform_util.h
+++ b/chrome/browser/platform_util.h
@@ -22,12 +22,18 @@ namespace platform_util {
 // Show the given file in a file manager. If possible, select the file.
 // The |profile| is used to determine the running profile of file manager app
 // in Chrome OS only. Not used in other platforms.
-// Must be called from the UI thread.
+// Must be called on the UI thread.
 void ShowItemInFolder(Profile* profile, const base::FilePath& full_path);
 
-// Open the given file in the desktop's default manner.
-// Must be called from the UI thread.
-void OpenItem(Profile* profile, const base::FilePath& full_path);
+// Opens the given file in the desktop's default manner. |full_path| must point
+// to an existing file. If |full_path| doesn't refer to an existing file, then
+// no action will be taken. Must be called on the UI thread.
+void OpenFile(Profile* profile, const base::FilePath& full_path);
+
+// Opens the given folder in the file manager. No action will be taken if
+// |full_path| does not refer to an existing folder. Must be called on the UI
+// thread.
+void OpenFolder(Profile* profile, const base::FilePath& full_path);
 
 // Open the given external protocol URL in the desktop's default manner.
 // (For example, mailto: URLs in the default mail user agent.)