mac: Tentative fix for Yosemite open file crash.

chrome/browser/chrome_browser_main_mac.mm

Index: chrome/browser/chrome_browser_main_mac.mm
diff --git a/chrome/browser/chrome_browser_main_mac.mm b/chrome/browser/chrome_browser_main_mac.mm
index 4fcf17fef974337eaeb76ec902121e5d954f0844..7c15afc39204cf8c1c2096c7256df15939b114de 100644
--- a/chrome/browser/chrome_browser_main_mac.mm
+++ b/chrome/browser/chrome_browser_main_mac.mm
@@ -259,7 +259,14 @@ void ChromeBrowserMainPartsMac::PreMainMessageLoopStart() {
       // in the window server, which is the default when not not using the
       // 10.9 SDK.
       // TODO: Remove this when we build with the 10.9 SDK.
-      @"NSWindowHostsLayersInWindowServer": @(base::mac::IsOSMavericksOrLater())
+      @"NSWindowHostsLayersInWindowServer":
+          @(base::mac::IsOSMavericksOrLater()),
+      // This setting prevents views from ditching their layers when the view
+      // gets removed from the view hierarchy. It defaults to YES for
+      // applications linked against an OSX 10.8+ SDK. In Yosemite, failing to
+      // set this to YES causes an AppKit crash. http://crbug.com/428977
+      // TODO(erikchen): Remove this when we build with an OSX 10.8+ SDK.
+      @"NSViewKeepLayersAround": @(YES)
   }];
 }