windows: Configure stack size for executables (fixes issue #3250)

Change the default stack size to 8 MiB for 64-bit and 0.5 MiB for 32-bit.

CEF's main thread needs at least a 1.5 MiB stack size in order to avoid
stack overflow crashes. However, if this is set in the PE file then other
threads get this size as well, leading to address-space exhaustion in 32-bit
CEF. A new CefRunWinMainWithPreferredStackSize function uses fibers to switch
the main thread to a 4 MiB stack (roughly the same effective size as the
64-bit build's 8 MiB stack) before running any other code.

This change additionally moves the existing Windows-only functions
CefSetOSModalLoop and CefEnableHighDPISupport from cef_app.h to cef_win.h.

libcef/common/base_impl.cc

@@ -12,10 +12,6 @@
 #include "base/threading/platform_thread.h"
 #include "base/trace_event/trace_event.h"
 
-#if BUILDFLAG(IS_WIN)
-#include "base/win/win_util.h"
-#endif
-
 namespace {
 
 constexpr const char kCategory[] = "cef.client";
@@ -334,9 +330,3 @@ cef_get_current_platform_thread_handle() {
   return base::PlatformThread::CurrentHandle().platform_handle();
 #endif
 }
-
-void CefEnableHighDPISupport() {
-#if BUILDFLAG(IS_WIN)
-  base::win::EnableHighDPISupport();
-#endif
-}