mac: Disable CoreServices _CSCheckFix.

Under the sandbox, _CSCheckFix() can result in a lot of unnecessary
disk I/O.

Bug: 1110292
Change-Id: I8507156d75fa046b3d5be1d5b0121abce0967af1
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2401334
Commit-Queue: Greg Kerr <kerrnel@chromium.org>
Reviewed-by: Greg Kerr <kerrnel@chromium.org>
Cr-Commit-Position: refs/heads/master@{#805864}

content/renderer/renderer_main_platform_delegate_mac.mm

@@ -29,6 +29,7 @@ void DisableSystemServices() {
   CHECK_EQ(result, kCGErrorSuccess);
 
   sandbox::DisableLaunchServices();
+  sandbox::DisableCoreServicesCheckFix();
 }
 
 }  // namespace

sandbox/mac/system_services.cc

@@ -14,6 +14,10 @@ OSStatus SetApplicationIsDaemon(Boolean isDaemon);
 void _LSSetApplicationLaunchServicesServerConnectionStatus(
     uint64_t flags,
     bool (^connection_allowed)(CFDictionaryRef options));
+
+// See
+// https://github.com/WebKit/webkit/commit/8da694b0b3febcc262653d01a45e946ce91845ed.
+void _CSCheckFixDisable() API_AVAILABLE(macosx(10.15));
 }  // extern "C"
 
 namespace sandbox {
@@ -34,4 +38,10 @@ void DisableLaunchServices() {
       });
 }
 
+void DisableCoreServicesCheckFix() {
+  if (__builtin_available(macOS 10.15, *)) {
+    _CSCheckFixDisable();
+  }
+}
+
 }  // namespace sandbox

sandbox/mac/system_services.h

@@ -18,6 +18,14 @@ namespace sandbox {
 // it instructs system frameworks to not attempt to connect.
 SEATBELT_EXPORT void DisableLaunchServices();
 
+// Disables the CoresServices CheckFix list. CoreServices maintains a
+// compatability database of bugs and workarounds by bundle ID. The system
+// depends on check-in in to LaunchServices to obtain a shared memory mapping of
+// the database, but if that fails (e.g. under the sandbox), it scans entries
+// in /System/Library for individual bug fix lists. This call disables the
+// CheckFix list.
+SEATBELT_EXPORT void DisableCoreServicesCheckFix();
+
 }  // namespace sandbox
 
 #endif  // SANDBOX_MAC_SYSTEM_SERVICES_H_