Revert "[XProto] Obtain Xcursor path from libXcursor"

This reverts commit ad63f7bc.

Reason for revert: Causes many CRASHes:
https://ci.chromium.org/p/chromium/builders/ci/Linux%20CFI/18398#overview-tab

Original change's description:
> [XProto] Obtain Xcursor path from libXcursor
> 
> Some distros (eg. Gentoo) use a non-default libXcursor path, so the
> path (which was previously hardcoded) must now be obtained from
> libXcursor.  This patch uses dlopen()/dlsym() to get the path when
> available.
> 
> BUG=1127712
> R=​sky
> 
> Change-Id: Ib99dff0448c521c1a6cf8ad03bfe981572b9627c
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2410305
> Commit-Queue: Thomas Anderson <thomasanderson@chromium.org>
> Auto-Submit: Thomas Anderson <thomasanderson@chromium.org>
> Reviewed-by: Scott Violet <sky@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#807158}

TBR=sky@chromium.org,thomasanderson@chromium.org

Change-Id: I0337fe6838a1bcbde6d71166650db1424a83c8db
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: 1127712
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2413509Reviewed-by: Yoichi Osato <yoichio@chromium.org>
Commit-Queue: Yoichi Osato <yoichio@chromium.org>
Cr-Commit-Position: refs/heads/master@{#807352}

ui/base/x/x11_cursor_loader.cc

@@ -4,8 +4,6 @@
 
 #include "ui/base/x/x11_cursor_loader.h"
 
-#include <dlfcn.h>
-
 #include <limits>
 #include <string>
 
@@ -15,7 +13,6 @@
 #include "base/files/file_util.h"
 #include "base/memory/ref_counted_memory.h"
 #include "base/memory/scoped_refptr.h"
-#include "base/no_destructor.h"
 #include "base/sequence_checker.h"
 #include "base/stl_util.h"
 #include "base/strings/string_number_conversions.h"
@@ -31,10 +28,6 @@
 #include "ui/gfx/x/connection.h"
 #include "ui/gfx/x/xproto.h"
 
-extern "C" {
-const char* XcursorLibraryPath(void);
-}
-
 namespace ui {
 
 namespace {
@@ -127,41 +120,14 @@ std::string GetEnv(const std::string& var) {
   return value;
 }
 
-std::string CursorPathFromLibXcursor() {
-  struct DlCloser {
-    void operator()(void* ptr) const { dlclose(ptr); }
-  };
-
-  std::unique_ptr<void, DlCloser> lib(dlopen("libXcursor.so.1", RTLD_LAZY));
-  if (!lib)
-    return "";
-
-  if (auto* sym = reinterpret_cast<decltype(&XcursorLibraryPath)>(
-          dlsym(lib.get(), "XcursorLibraryPath"))) {
-    if (const char* path = sym())
-      return path;
-  }
-  return "";
-}
-
-std::string CursorPathImpl() {
+std::string CursorPath() {
   constexpr const char kDefaultPath[] =
       "~/.local/share/icons:~/.icons:/usr/share/icons:/usr/share/pixmaps:"
       "/usr/X11R6/lib/X11/icons";
-
-  auto libxcursor_path = CursorPathFromLibXcursor();
-  if (!libxcursor_path.empty())
-    return libxcursor_path;
-
   std::string path = GetEnv("XCURSOR_PATH");
   return path.empty() ? kDefaultPath : path;
 }
 
-const std::string& CursorPath() {
-  static base::NoDestructor<std::string> path(CursorPathImpl());
-  return *path;
-}
-
 x11::Render::PictFormat GetRenderARGBFormat(
     const x11::Render::QueryPictFormatsReply& formats) {
   for (const auto& format : formats.formats) {