Cleanup: Remove unused SharedMemory ctor.

base/memory/shared_memory.h

Index: base/memory/shared_memory.h
diff --git a/base/memory/shared_memory.h b/base/memory/shared_memory.h
index 18416c0fd0703b5c0ab56e5174134e4c69308496..b7a5ce1b4666e703c207aacf4423362e120cbde9 100644
--- a/base/memory/shared_memory.h
+++ b/base/memory/shared_memory.h
@@ -84,12 +84,14 @@ class BASE_EXPORT SharedMemory {
   // that |read_only| matches the permissions of the handle.
   SharedMemory(const SharedMemoryHandle& handle, bool read_only);
 
+#if defined(OS_WIN)
   // Create a new SharedMemory object from an existing, open
   // shared memory file that was created by a remote process and not shared
   // to the current process.
   SharedMemory(const SharedMemoryHandle& handle,
                bool read_only,
                ProcessHandle process);
+#endif
 
   // Closes any open files.
   ~SharedMemory();