Disable legacy hooking in the browser process

Ready for round 2. We're now aware of the side-effect of turning this
process mitigation for TSF IMEs (sets immersive mode) and we're ok with
it.

Bug: 557798
Change-Id: I2f2dbb3e6182f4d9cf05e1f97424a3959fde920b
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1721458Reviewed-by: Will Harris <wfh@chromium.org>
Commit-Queue: Patrick Monette <pmonette@chromium.org>
Cr-Commit-Position: refs/heads/master@{#681460}

chrome/chrome_elf/chrome_elf_main.cc

@@ -8,6 +8,7 @@
 #include <windows.h>
 
 #include "chrome/chrome_elf/blacklist/blacklist.h"
+#include "chrome/chrome_elf/chrome_elf_security.h"
 #include "chrome/chrome_elf/crash/crash_helper.h"
 #include "chrome/chrome_elf/third_party_dlls/main.h"
 #include "chrome/install_static/install_details.h"
@@ -70,6 +71,9 @@ BOOL APIENTRY DllMain(HMODULE module, DWORD reason, LPVOID reserved) {
     if (install_static::IsNonBrowserProcess())
       return TRUE;
 
+    // Disable legacy hooking.
+    elf_security::EarlyBrowserSecurity();
+
     __try {
       // Initialize blacklist before initializing third_party_dlls.
       // Note: "blacklist" is deprecated in favor of "third_party_dlls", but