content: Some code cleanup related to shared memory allocation.

content/child/child_thread_impl.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef CONTENT_CHILD_CHILD_THREAD_IMPL_H_
 #define CONTENT_CHILD_CHILD_THREAD_IMPL_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
@@ skipping 97 matching lines @@
   const service_manager::ServiceInfo& GetChildServiceInfo() const;
   const service_manager::ServiceInfo& GetBrowserServiceInfo() const;
   bool IsConnectedToBrowser() const;
 
   IPC::SyncChannel* channel() { return channel_.get(); }
 
   IPC::MessageRouter* GetRouter();
 
   mojom::RouteProvider* GetRemoteRouteProvider();
 
-  // Allocates a block of shared memory of the given size. Returns NULL on
-  // failure.
-  // Note: On posix, this requires a sync IPC to the browser process,
-  // but on windows the child process directly allocates the block.
-  std::unique_ptr<base::SharedMemory> AllocateSharedMemory(size_t buf_size);
-
-  // A static variant that can be called on background threads provided
-  // the |sender| passed in is safe to use on background threads.
+  // A static variant that can be called on background threads.
   // |out_of_memory| is an output variable populated on failure which tells the
   // caller whether the failure was caused by an out of memory error.
   static std::unique_ptr<base::SharedMemory> AllocateSharedMemory(
       size_t buf_size,
-      IPC::Sender* sender,
-      bool* out_of_memory);
+      bool* out_of_memory = nullptr);
 
 #if defined(OS_LINUX)
   void SetThreadPriority(base::PlatformThreadId id,
                          base::ThreadPriority priority);
 #endif
 
   ChildSharedBitmapManager* shared_bitmap_manager() const {
     return shared_bitmap_manager_.get();
   }
 
@@ skipping 235 matching lines @@
 
  private:
   struct Options options_;
 
   DISALLOW_COPY_AND_ASSIGN(Builder);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_CHILD_CHILD_THREAD_IMPL_H_