Revert of discardable_memory: Using mojo IPC to replace Chrome IPC

content/child/child_thread_impl.h

Index: content/child/child_thread_impl.h
diff --git a/content/child/child_thread_impl.h b/content/child/child_thread_impl.h
index 9cdc07bf1200ae400af21e47dbdbe790aa9e985c..6a2aa5afd763a00aa74469f5e8a7886fc82b2896 100644
--- a/content/child/child_thread_impl.h
+++ b/content/child/child_thread_impl.h
@@ -15,7 +15,7 @@
 #include "base/memory/shared_memory.h"
 #include "base/memory/weak_ptr.h"
 #include "base/power_monitor/power_monitor.h"
-#include "base/single_thread_task_runner.h"
+#include "base/sequenced_task_runner.h"
 #include "base/tracked_objects.h"
 #include "build/build_config.h"
 #include "content/common/associated_interfaces.mojom.h"
@@ -47,6 +47,10 @@
 class ScopedIPCSupport;
 }  // namespace edk
 }  // namespace mojo
+
+namespace discardable_memory {
+class ClientDiscardableSharedMemoryManager;
+}  // namespace discardable_memory
 
 namespace content {
 class ChildHistogramMessageFilter;
@@ -83,6 +87,7 @@
   // should be joined in Shutdown().
   ~ChildThreadImpl() override;
   virtual void Shutdown();
+  void ShutdownDiscardableSharedMemoryManager();
 
   // IPC::Sender implementation:
   bool Send(IPC::Message* msg) override;
@@ -134,6 +139,11 @@
     return shared_bitmap_manager_.get();
   }
 
+  discardable_memory::ClientDiscardableSharedMemoryManager*
+  discardable_shared_memory_manager() const {
+    return discardable_shared_memory_manager_.get();
+  }
+
   ResourceDispatcher* resource_dispatcher() const {
     return resource_dispatcher_.get();
   }
@@ -215,7 +225,7 @@
   void OnChannelError() override;
 
   bool IsInBrowserProcess() const;
-  scoped_refptr<base::SingleThreadTaskRunner> GetIOTaskRunner();
+  scoped_refptr<base::SequencedTaskRunner> GetIOTaskRunner();
 
  private:
   class ChildThreadMessageRouter : public IPC::MessageRouter {
@@ -230,6 +240,8 @@
    private:
     IPC::Sender* const sender_;
   };
+
+  class ClientDiscardableSharedMemoryManagerDelegate;
 
   void Init(const Options& options);
 
@@ -318,9 +330,15 @@
 
   std::unique_ptr<ChildSharedBitmapManager> shared_bitmap_manager_;
 
+  std::unique_ptr<discardable_memory::ClientDiscardableSharedMemoryManager>
+      discardable_shared_memory_manager_;
+
+  std::unique_ptr<ClientDiscardableSharedMemoryManagerDelegate>
+      client_discardable_shared_memory_manager_delegate_;
+
   std::unique_ptr<base::PowerMonitor> power_monitor_;
 
-  scoped_refptr<base::SingleThreadTaskRunner> browser_process_io_runner_;
+  scoped_refptr<base::SequencedTaskRunner> browser_process_io_runner_;
 
   std::unique_ptr<base::WeakPtrFactory<ChildThreadImpl>>
       channel_connected_factory_;
@@ -338,7 +356,7 @@
 
   bool auto_start_service_manager_connection;
   bool connect_to_browser;
-  scoped_refptr<base::SingleThreadTaskRunner> browser_process_io_runner;
+  scoped_refptr<base::SequencedTaskRunner> browser_process_io_runner;
   std::vector<IPC::MessageFilter*> startup_filters;
   std::string in_process_service_request_token;