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 6a2aa5afd763a00aa74469f5e8a7886fc82b2896..414f9de1ed3226ca843f31eb9edc19896d60fa49 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/sequenced_task_runner.h"
+#include "base/single_thread_task_runner.h"
 #include "base/tracked_objects.h"
 #include "build/build_config.h"
 #include "content/common/associated_interfaces.mojom.h"
@@ -225,7 +225,7 @@ class CONTENT_EXPORT ChildThreadImpl
   void OnChannelError() override;
 
   bool IsInBrowserProcess() const;
-  scoped_refptr<base::SequencedTaskRunner> GetIOTaskRunner();
+  scoped_refptr<base::SingleThreadTaskRunner> GetIOTaskRunner();
 
  private:
   class ChildThreadMessageRouter : public IPC::MessageRouter {
@@ -241,8 +241,6 @@ class CONTENT_EXPORT ChildThreadImpl
     IPC::Sender* const sender_;
   };
 
-  class ClientDiscardableSharedMemoryManagerDelegate;
-
   void Init(const Options& options);
 
   // We create the channel first without connecting it so we can add filters
@@ -333,12 +331,9 @@ class CONTENT_EXPORT ChildThreadImpl
   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::SequencedTaskRunner> browser_process_io_runner_;
+  scoped_refptr<base::SingleThreadTaskRunner> browser_process_io_runner_;
 
   std::unique_ptr<base::WeakPtrFactory<ChildThreadImpl>>
       channel_connected_factory_;
@@ -356,7 +351,8 @@ struct ChildThreadImpl::Options {
 
   bool auto_start_service_manager_connection;
   bool connect_to_browser;
-  scoped_refptr<base::SequencedTaskRunner> browser_process_io_runner;
+  bool init_discardable_memory;

[reveman, 2016/11/15 16:13:20]

why do we need a flag for this now instead of creating a manager unconditionally
as before?

[Peng, 2016/11/15 19:04:05]

Because we currently only expose the discardable memory service to pepper plugin
and renderer(currently the discardable memory is only available to browser,
renderer and plugin processes), so we have to only init it for right processes.
Otherwise, some processes (GPU, utility processes) will crash.

+  scoped_refptr<base::SingleThreadTaskRunner> browser_process_io_runner;
   std::vector<IPC::MessageFilter*> startup_filters;
   std::string in_process_service_request_token;
 
@@ -370,6 +366,7 @@ class ChildThreadImpl::Options::Builder {
 
   Builder& InBrowserProcess(const InProcessChildThreadParams& params);
   Builder& AutoStartServiceManagerConnection(bool auto_start);
+  Builder& InitDiscardableMemory(bool discardable_memory);
   Builder& ConnectToBrowser(bool connect_to_browser);
   Builder& AddStartupFilter(IPC::MessageFilter* filter);