Disable Quick View by default and add about flag to enable it.

chromeos/chromeos_switches.cc

Index: chromeos/chromeos_switches.cc
diff --git a/chromeos/chromeos_switches.cc b/chromeos/chromeos_switches.cc
index 1d0fccf30519829dc534b8dfddfea72618e0f1b9..21c00f8b12159515c6abd8772a97b534d92a6d74 100644
--- a/chromeos/chromeos_switches.cc
+++ b/chromeos/chromeos_switches.cc
@@ -83,7 +83,7 @@ const char kDisableCloudImport[] = "disable-cloud-import";
 // Disables the ChromeOS demo.
 const char kDisableDemoMode[] = "disable-demo-mode";
 
-// Disable quick view in Files app.
+// Disables quick view in Files app.
 const char kDisableFilesQuickView[] = "disable-files-quick-view";
 
 // Disable HID-detection OOBE screen.
@@ -137,6 +137,9 @@ const char kEnableConsumerManagement[] = "enable-consumer-management";
 // Enables details panel in Files app.
 const char kEnableFilesDetailsPanel[] = "enable-files-details-panel";
 
+// Enables quick view in Files app.
+const char kEnableFilesQuickView[] = "enable-files-quick-view";
+
 // Disables notification when device is in end of life status.
 const char kDisableEolNotification[] = "disable-eol-notification";