cros: Remove unused low memory margin code from sandbox and zygote

content/public/browser/zygote_host_linux.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_PUBLIC_BROWSER_ZYGOTE_HOST_LINUX_H_
 #define CONTENT_PUBLIC_BROWSER_ZYGOTE_HOST_LINUX_H_
 
 #include <unistd.h>
 
 #include "base/process/process.h"
@@ skipping 20 matching lines @@
 
   // Returns an int which is a bitmask of kSandboxLinux* values. Only valid
   // after the first render has been forked.
   virtual int GetSandboxStatus() const = 0;
 
   // Adjust the OOM score of the given renderer's PID.  The allowed
   // range for the score is [0, 1000], where higher values are more
   // likely to be killed by the OOM killer.
   virtual void AdjustRendererOOMScore(base::ProcessHandle process_handle,
                                       int score) = 0;
-
-  // Adjust the point at which the low memory notifier in the kernel tells
-  // us that we're low on memory.  When there is less than |margin_mb| left,
-  // then the notifier will notify us.  Set |margin_mb| to -1 to turn off
-  // low memory notification altogether.
-  virtual void AdjustLowMemoryMargin(int64 margin_mb) = 0;
 };
 
 }  // namespace content
 
 #endif  // CONTENT_PUBLIC_BROWSER_ZYGOTE_HOST_LINUX_H_