Implemented swipe to close in overview mode.

ash/ash_switches.cc

Index: ash/ash_switches.cc
diff --git a/ash/ash_switches.cc b/ash/ash_switches.cc
index 1240839ba855551c80f697eec7b543627ed40928..a54496fd7a274548844e4032d3c5669551782490 100644
--- a/ash/ash_switches.cc
+++ b/ash/ash_switches.cc
@@ -42,6 +42,10 @@ const char kAshDefaultWallpaperSmall[] = "ash-default-wallpaper-small";
 // WorkspaceLayoutManager.
 const char kAshDisableLockLayoutManager[] = "ash-disable-lock-layout-manager";
 
+// Disables gesture swipe to close windows while in Overview mode.
+const char kAshDisableSwipeToCloseInOverviewMode[] =
+    "ash-disable-swipe-to-close-in-overview-mode";
+
 // Disable the Touch Exploration Mode. Touch Exploration Mode will no longer be
 // turned on automatically when spoken feedback is enabled when this flag is
 // set.