Revert of discardable_memory: Using mojo IPC to replace Chrome IPC

content/ppapi_plugin/ppapi_thread.h

Index: content/ppapi_plugin/ppapi_thread.h
diff --git a/content/ppapi_plugin/ppapi_thread.h b/content/ppapi_plugin/ppapi_thread.h
index ed41b2f7089bd02e32d4ce883cc1b3fc33c49902..43bcd398bbf13a8ec71b3a97da6dd9bc44d05e97 100644
--- a/content/ppapi_plugin/ppapi_thread.h
+++ b/content/ppapi_plugin/ppapi_thread.h
@@ -34,10 +34,6 @@
 namespace base {
 class CommandLine;
 class FilePath;
-}
-
-namespace discardable_memory {
-class ClientDiscardableSharedMemoryManager;
 }
 
 namespace IPC {
@@ -185,9 +181,6 @@
 
   variations::ChildProcessFieldTrialSyncer field_trial_syncer_;
 
-  std::unique_ptr<discardable_memory::ClientDiscardableSharedMemoryManager>
-      discardable_shared_memory_manager_;
-
   DISALLOW_IMPLICIT_CONSTRUCTORS(PpapiThread);
 };