[Mac] Shut down connections to WindowServer before engaging the sandbox.

content/common/sandbox_mac.mm

Index: content/common/sandbox_mac.mm
diff --git a/content/common/sandbox_mac.mm b/content/common/sandbox_mac.mm
index 9ef3e1c6cdcad0f1c44e32102d7912bef2a1225e..a191cdc74edd474b3cada6b895e1bcaafa7282b6 100644
--- a/content/common/sandbox_mac.mm
+++ b/content/common/sandbox_mac.mm
@@ -38,6 +38,11 @@ extern "C" {
 #include "ui/base/layout.h"
 #include "ui/gl/gl_surface.h"
 
+extern "C" {
+void CGSSetDenyWindowServerConnections(bool);
+void CGSShutdownServerConnections();
+};
+
 namespace content {
 namespace {
 
@@ -268,8 +273,8 @@ void Sandbox::SandboxWarmup(int sandbox_type) {
         kCGImageAlphaPremultipliedFirst | kCGBitmapByteOrder32Host));
 
     // Load in the color profiles we'll need (as a side effect).
-    (void) base::mac::GetSRGBColorSpace();
-    (void) base::mac::GetSystemColorSpace();
+    ignore_result(base::mac::GetSRGBColorSpace());
+    ignore_result(base::mac::GetSystemColorSpace());
 
     // CGColorSpaceCreateSystemDefaultCMYK - 10.6
     base::ScopedCFTypeRef<CGColorSpaceRef> cmyk_colorspace(
@@ -325,6 +330,14 @@ void Sandbox::SandboxWarmup(int sandbox_type) {
     NSColor* color = [NSColor controlTextColor];
     [color colorUsingColorSpaceName:NSCalibratedRGBColorSpace];
   }
+
+  if (sandbox_type == SANDBOX_TYPE_RENDERER) {
+    // Now disconnect from WindowServer, after all objects have been warmed up.
+    // Shutting down the connection requires connecting to WindowServer,
+    // so do this before actually engaging the sandbox.
+    CGSSetDenyWindowServerConnections(true);
+    CGSShutdownServerConnections();
+  }
 }
 
 // static