Remove tcmalloc when not being used. Restore shim on Windows.

base/allocator/generic_allocators.cc

Index: base/allocator/generic_allocators.cc
diff --git a/base/allocator/generic_allocators.cc b/base/allocator/generic_allocators.cc
index d12f3b976ac274c4526cc25ad143b130f0ac0203..2726903faf3589e5f247a34c6eaf133b5a57c110 100644
--- a/base/allocator/generic_allocators.cc
+++ b/base/allocator/generic_allocators.cc
@@ -16,7 +16,7 @@ inline void* generic_cpp_alloc(size_t size, bool nothrow) {
     ptr = malloc(size);
     if (ptr)
       return ptr;
-    if (!call_new_handler(nothrow))
+    if (!call_new_handler(nothrow, size))
       break;
   }
   return ptr;
@@ -83,7 +83,7 @@ void* calloc(size_t n, size_t elem_size) {
   return result;
 }
 
-void cfree(void* p) __THROW {
+void cfree(void* p) {
   free(p);
 }