Add the PE's IMAGE_LOAD_CONFIG_DIRECTORY for chrome.exe

chrome/app/chrome_exe_load_config_win.cc

Index: chrome/app/chrome_exe_load_config_win.cc
diff --git a/chrome/app/chrome_exe_load_config_win.cc b/chrome/app/chrome_exe_load_config_win.cc
new file mode 100644
index 0000000000000000000000000000000000000000..712b8a3c3481d927fcfdffa4d6bedbc1572e845c
--- /dev/null
+++ b/chrome/app/chrome_exe_load_config_win.cc
@@ -0,0 +1,114 @@
+// Copyright (c) 2015 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.
+
+#include <windows.h>
+
+// The whole object of this file is to define |_load_config_used| which
+// is a weakly-linked symbol that the linker knows about. The crt defines
+// as well it but this one will be used if present.

[brucedawson, 2015/05/13 17:50:46]

Missing word 'it': "it as well"...

+//
+// The _load_config_used appears in the exe as a special member of the PE
+// image format: the load config directory. This structure controls
+// global parameters which are hard or impossible to set otherwise. This
+// MSDN page https://goo.gl/zsGeVY documents some of the members.
+//
+// When making a changes to this stucture the only practical way to make
+// sure they are honored is to run dumpbin.exe <exe-file> /loadconfig
+// and inspect the results.

[brucedawson, 2015/05/13 17:50:46]

I also wrote a tool (85 lines of PE parsing) that allows slamming the
DeCommitTotalFreeThreshold of a PE file, FWIW. It also dumps the old value.
Should it be checked in somewhere?

+
+#if defined(_WIN64)
+typedef struct {
+  DWORD      Size;
+  DWORD      TimeDateStamp;
+  WORD       MajorVersion;
+  WORD       MinorVersion;
+  DWORD      GlobalFlagsClear;
+  DWORD      GlobalFlagsSet;
+  DWORD      CriticalSectionDefaultTimeout;
+  ULONGLONG  DeCommitFreeBlockThreshold;
+  ULONGLONG  DeCommitTotalFreeThreshold;
+  ULONGLONG  LockPrefixTable;
+  ULONGLONG  MaximumAllocationSize;
+  ULONGLONG  VirtualMemoryThreshold;
+  ULONGLONG  ProcessAffinityMask;
+  DWORD      ProcessHeapFlags;
+  WORD       CSDVersion;
+  WORD       Reserved1;
+  ULONGLONG  EditList;
+  ULONGLONG  SecurityCookie;
+  ULONGLONG  SEHandlerTable;
+  ULONGLONG  SEHandlerCount;
+} IMAGE_LOAD_CONFIG_DIRECTORY64_2;
+typedef IMAGE_LOAD_CONFIG_DIRECTORY64_2 IMAGE_LOAD_CONFIG_DIRECTORY_2;
+#else
+typedef struct {
+  DWORD       Size;
+  DWORD       TimeDateStamp;
+  WORD        MajorVersion;
+  WORD        MinorVersion;
+  DWORD       GlobalFlagsClear;
+  DWORD       GlobalFlagsSet;
+  DWORD       CriticalSectionDefaultTimeout;
+  DWORD       DeCommitFreeBlockThreshold;
+  DWORD       DeCommitTotalFreeThreshold;
+  DWORD       LockPrefixTable;
+  DWORD       MaximumAllocationSize;
+  DWORD       VirtualMemoryThreshold;
+  DWORD       ProcessHeapFlags;
+  DWORD       ProcessAffinityMask;
+  WORD        CSDVersion;
+  WORD        Reserved1;
+  DWORD       EditList;
+  PUINT_PTR   SecurityCookie;
+  PVOID       *SEHandlerTable;
+  DWORD       SEHandlerCount;
+} IMAGE_LOAD_CONFIG_DIRECTORY32_2;
+typedef IMAGE_LOAD_CONFIG_DIRECTORY32_2 IMAGE_LOAD_CONFIG_DIRECTORY_2;
+#endif
+
+// What follows, except as indicated is verbatim (including casts) from
+// <visual studio path>\VC\crt\src\intel\loadcfg.c. The default values
+// are all 0 except for the last 3 members. See
+// https://msdn.microsoft.com/en-us/library/9a89h429.aspx for an
+// explanation of these members.
+extern "C" UINT_PTR __security_cookie;
+extern "C" PVOID __safe_se_handler_table[];
+extern "C" BYTE __safe_se_handler_count;
+
+// DeCommitTotalFreeThreshold: increase the decomit free threshold for
+// the process heap, which is documented as "The size of the minimum
+// total memory that must be freed in the process heap before it is
+// freed (de-committed) in bytes".
+//
+// Set at 2 MiB what this does is prevent a lot of VirtualFree plus the
+// following VirtualAlloc because the default value makes the heap too
+// conservative on the ammount of memory it keeps for future allocations.
+
+extern "C"
+const IMAGE_LOAD_CONFIG_DIRECTORY_2  _load_config_used = {
+  sizeof(IMAGE_LOAD_CONFIG_DIRECTORY_2),
+  0,  // TimeDateStamp.
+  0,  // MajorVersion.
+  0,  // MinorVersion.
+  0,  // GlobalFlagsClear.
+  0,  // GlobalFlagsSet.
+  0,  // CriticalSectionDefaultTimeout.
+  0,  // DeCommitFreeBlockThreshold.
+  2 * 1024 * 1024,  // DeCommitTotalFreeThreshold.
+  0,  // LockPrefixTable.
+  0,  // MaximumAllocationSize.
+  0,  // VirtualMemoryThreshold.
+  0,  // ProcessHeapFlags.
+  0,  // ProcessAffinityMask.
+  0,  // CSDVersion.
+  0,  // Reserved1.
+  0 , // EditList.
+#ifdef _WIN64
+  (ULONGLONG)&__security_cookie,
+#else
+  &__security_cookie,
+  __safe_se_handler_table,
+  (DWORD)(DWORD_PTR)&__safe_se_handler_count
+#endif
+};