Give base::SharedMemory::CreateAnonymous an executable flag

content/public/common/child_process_sandbox_support_linux.h

Index: content/public/common/child_process_sandbox_support_linux.h
diff --git a/content/public/common/child_process_sandbox_support_linux.h b/content/public/common/child_process_sandbox_support_linux.h
index c373ba45e709dc546538cc985e5046fb6f2100cf..0dbef685cf95d010f87470a7bd8f486064f0d082 100644
--- a/content/public/common/child_process_sandbox_support_linux.h
+++ b/content/public/common/child_process_sandbox_support_linux.h
@@ -14,8 +14,9 @@
 namespace content {
 
 // Returns a file descriptor for a shared memory segment.
-// The second argument is ignored because SHM segments are always
-// mappable with PROT_EXEC on Linux.
+// The executable flag indicates that we'll need to use mprotect
+// with PROT_EXEC after making a mapping, but not that we'll need
+// to mmap with PROT_EXEC in the first place.
 CONTENT_EXPORT int MakeSharedMemorySegmentViaIPC(size_t length,
                                                  bool executable);