Enable memory profiler on Linux when TC_MALLOC is enabled.

base/profiler/alternate_timer.h

Index: base/profiler/alternate_timer.h
===================================================================
--- base/profiler/alternate_timer.h	(revision 150216)
+++ base/profiler/alternate_timer.h	(working copy)
@@ -23,13 +23,14 @@
 // 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.