Move cc::DisplayItemList and related classes into cc/paint/

cc/base/completion_event.h

Index: cc/base/completion_event.h
diff --git a/cc/base/completion_event.h b/cc/base/completion_event.h
index edee0b78bf0e7bff28b07b878faae6a2ea858cce..48865082a5e555f32526927bfac1a46ebb40c0a3 100644
--- a/cc/base/completion_event.h
+++ b/cc/base/completion_event.h
@@ -9,6 +9,7 @@
 #include "base/synchronization/waitable_event.h"
 #include "base/threading/thread_restrictions.h"
 #include "base/time/time.h"
+#include "cc/base/base_export.h"
 
 namespace cc {
 
@@ -16,7 +17,7 @@ namespace cc {
 // absolutely certain that doing-so will not lead to a deadlock.
 //
 // It is safe to destroy this object as soon as Wait() returns.
-class CompletionEvent {
+class CC_BASE_EXPORT CompletionEvent {
  public:
   CompletionEvent()
       : event_(base::WaitableEvent::ResetPolicy::AUTOMATIC,