Revert of Process Statistics header, add max RSS to render_pdfs

tools/ProcStats.cpp

-/*
- * Copyright 2014 Google Inc.
- *
- * Use of this source code is governed by a BSD-style license that can be
- * found in the LICENSE file.
- */
-
-#include "ProcStats.h"
-
-#if defined(SK_BUILD_FOR_UNIX) || \
-    defined(SK_BUILD_FOR_MAC) || \
-    defined(SK_BUILD_FOR_ANDROID)
-
-    #include <sys/resource.h>
-    int sk_tools::getMaxResidentSetSizeKB() {
-        struct rusage ru;
-        getrusage(RUSAGE_SELF, &ru);
-    #if defined(SK_BUILD_FOR_MAC)
-        return static_cast<int>(ru.ru_maxrss / 1024);  // Darwin reports bytes.
-    #else
-        return static_cast<int>(ru.ru_maxrss);  // Linux reports kilobytes.
-    #endif
-    }
-
-#else
-
-    int sk_tools::getMaxResidentSetSizeKB() {
-        return -1;
-    }
-
-#endif