Enable memory profiler on Linux when TC_MALLOC is enabled.

base/profiler/alternate_timer.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.
 
 // This is a glue file, which allows third party code to call into our profiler
 // without having to include most any functions from base.
 
 #ifndef BASE_PROFILER_ALTERNATE_TIMER_H_
 #define BASE_PROFILER_ALTERNATE_TIMER_H_
 
 #include "base/base_export.h"
 
 namespace tracked_objects {
 
 enum TimeSourceType {
   TIME_SOURCE_TYPE_WALL_TIME,
   TIME_SOURCE_TYPE_TCMALLOC
 };
 
 // Provide type for an alternate timer function.
 typedef unsigned int NowFunction();
 
 // Environment variable name that is used to activate alternate timer profiling
 // (such as using TCMalloc allocations to provide a pseudo-timer) for tasks
 // instead of wall clock profiling.
-extern const char kAlternateProfilerTime[];
+BASE_EXPORT extern const char kAlternateProfilerTime[];
 
 // Set an alternate timer function to replace the OS time function when
 // profiling.  Typically this is called by an allocator that is providing a
 // function that indicates how much memory has been allocated on any given
 // thread.
-void SetAlternateTimeSource(NowFunction* now_function, TimeSourceType type);
+BASE_EXPORT void SetAlternateTimeSource(NowFunction* now_function,
+                                        TimeSourceType type);
 
 // Gets the pointer to a function that was set via SetAlternateTimeSource().
 // Returns NULL if no set was done prior to calling GetAlternateTimeSource.
 NowFunction* GetAlternateTimeSource();
 
 // Returns the type of the currently set time source.
 BASE_EXPORT TimeSourceType GetTimeSourceType();
 
 }  // namespace tracked_objects
 
 #endif  // BASE_PROFILER_ALTERNATE_TIMER_H_