diff --git a/ipc/glue/SharedMemory.h b/ipc/glue/SharedMemory.h
index c7c230389e16..9c2f6bf6785e 100644
--- a/ipc/glue/SharedMemory.h
+++ b/ipc/glue/SharedMemory.h
@@ -51,6 +51,7 @@ class SharedMemory {
 
   virtual bool Create(size_t size) = 0;
   virtual bool Map(size_t nBytes, void* fixed_address = nullptr) = 0;
+  virtual void Unmap() = 0;
 
   virtual void CloseHandle() = 0;
 
diff --git a/ipc/glue/SharedMemoryBasic_android.h b/ipc/glue/SharedMemoryBasic_android.h
index 6e6eddeac1fa..7376a2a78653 100644
--- a/ipc/glue/SharedMemoryBasic_android.h
+++ b/ipc/glue/SharedMemoryBasic_android.h
@@ -34,6 +34,8 @@ class SharedMemoryBasic final
 
   virtual bool Map(size_t nBytes, void* fixed_address = nullptr) override;
 
+  virtual void Unmap() override;
+
   virtual void CloseHandle() override;
 
   virtual void* memory() const override {
@@ -60,8 +62,6 @@ class SharedMemoryBasic final
  private:
   ~SharedMemoryBasic();
 
-  void Unmap();
-
   // The /dev/ashmem fd we allocate.
   int mShmFd;
   // Pointer to mapped region, null if unmapped.
diff --git a/ipc/glue/SharedMemoryBasic_chromium.h b/ipc/glue/SharedMemoryBasic_chromium.h
index 09ec1b60e0fc..933a06b73370 100644
--- a/ipc/glue/SharedMemoryBasic_chromium.h
+++ b/ipc/glue/SharedMemoryBasic_chromium.h
@@ -49,6 +49,8 @@ class SharedMemoryBasic final
     return ok;
   }
 
+  virtual void Unmap() override { mSharedMemory.Unmap(); }
+
   virtual void CloseHandle() override { mSharedMemory.Close(false); }
 
   virtual void* memory() const override {
diff --git a/ipc/glue/SharedMemoryBasic_mach.h b/ipc/glue/SharedMemoryBasic_mach.h
index fd2885b8d2b5..c2acf2e1553f 100644
--- a/ipc/glue/SharedMemoryBasic_mach.h
+++ b/ipc/glue/SharedMemoryBasic_mach.h
@@ -73,6 +73,8 @@ class SharedMemoryBasic final : public SharedMemoryCommon<mach_port_t> {
 
   virtual bool Map(size_t nBytes, void* fixed_address = nullptr) override;
 
+  virtual void Unmap() override;
+
   virtual void CloseHandle() override;
 
   virtual void* memory() const override {
@@ -97,7 +99,6 @@ class SharedMemoryBasic final : public SharedMemoryCommon<mach_port_t> {
  private:
   ~SharedMemoryBasic();
 
-  void Unmap();
   mach_port_t mPort;
   // Pointer to mapped region, null if unmapped.
   void* mMemory;