Move OneWriterSeqLock and SharedMemorySeqLockBuffer from content/ to device/base/synchronization

device/base/synchronization/BUILD.gn

Index: device/base/synchronization/BUILD.gn
diff --git a/components/pdf/common/BUILD.gn b/device/base/synchronization/BUILD.gn
similarity index 59%
copy from components/pdf/common/BUILD.gn
copy to device/base/synchronization/BUILD.gn
index adff35e0ba6aa6d004194a4d10a576fb81e840bc..42fa93efbdb9e31be4207ee811b7ea505bccda32 100644
--- a/components/pdf/common/BUILD.gn
+++ b/device/base/synchronization/BUILD.gn
@@ -4,17 +4,14 @@
 
 import("//build/config/features.gni")
 
-static_library("common") {
+source_set("synchronization") {
   sources = [
-    "pdf_message_generator.cc",
-    "pdf_message_generator.h",
-    "pdf_messages.h",
+    "one_writer_seqlock.cc",
+    "one_writer_seqlock.h",
+    "shared_memory_seqlock_buffer.h",
   ]
 
   deps = [
     "//base",
-    "//content/public/common",
-    "//ipc",
-    "//url",
   ]
 }