Revert "Disable legacy hooking in the browser process"

This reverts commit f87359ae.

Reason for revert: https://crbug.com/1017694

Some legacy IMEs (ex: Yahoo Chinese IME) are broken with this change.

Bug: 1017694
Change-Id: I0dceabbd5ee712c74aab113e912a3e629f79785a
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1880597Reviewed-by: Patrick Monette <pmonette@chromium.org>
Commit-Queue: Patrick Monette <pmonette@chromium.org>
Cr-Commit-Position: refs/heads/master@{#709983}

chrome/chrome_elf/chrome_elf_main.cc

@@ -7,7 +7,6 @@
 #include <assert.h>
 #include <windows.h>
 
-#include "chrome/chrome_elf/chrome_elf_security.h"
 #include "chrome/chrome_elf/crash/crash_helper.h"
 #include "chrome/chrome_elf/third_party_dlls/beacon.h"
 #include "chrome/chrome_elf/third_party_dlls/main.h"
@@ -71,9 +70,6 @@ BOOL APIENTRY DllMain(HMODULE module, DWORD reason, LPVOID reserved) {
     if (install_static::IsNonBrowserProcess())
       return TRUE;
 
-    // Disable legacy hooking.
-    elf_security::EarlyBrowserSecurity();
-
     __try {
       // Initialize the blocking of third-party DLLs if the initialization of
       // the safety beacon succeeds.