Support sideloaded fonts via command line option for blink layout_tests

content/shell/app/webkit_test_platform_support_win.cc

Index: content/shell/app/webkit_test_platform_support_win.cc
diff --git a/content/shell/app/webkit_test_platform_support_win.cc b/content/shell/app/webkit_test_platform_support_win.cc
index 34c3213b577670ef659f8dd1e64d7aba77a2bd55..536d22e15ba474204906572015071bc4bafb9244 100644
--- a/content/shell/app/webkit_test_platform_support_win.cc
+++ b/content/shell/app/webkit_test_platform_support_win.cc
@@ -9,11 +9,13 @@
 #include <list>
 #include <string>
 
+#include "base/command_line.h"
 #include "base/file_util.h"
 #include "base/files/file_path.h"
 #include "base/logging.h"
 #include "base/path_service.h"
 #include "base/strings/utf_string_conversions.h"
+#include "content/shell/common/shell_switches.h"
 
 #define SIZEOF_STRUCT_WITH_SPECIFIED_LAST_MEMBER(struct_name, member) \
     offsetof(struct_name, member) + \
@@ -34,6 +36,12 @@ bool SetupFonts() {
   base::FilePath font_path =
       base_path.Append(FILE_PATH_LITERAL("/AHEM____.TTF"));
 
+  // We do two registrations:
+  // 1. For GDI font rendering via ::AddFontMemResourceEx.
+  // 2. For DirectWrite rendering by appending a command line flag that tells
+  //    the sandbox policy/warmup to grant access to the given path.
+
+  // GDI registration.
   std::string font_buffer;
   if (!base::ReadFileToString(font_path, &font_buffer)) {
     std::cerr << "Failed to load font " << base::WideToUTF8(font_path.value())
@@ -51,6 +59,12 @@ bool SetupFonts() {
     std::cerr << "Failed to register Ahem font\n";
     return false;
   }
+
+  // DirectWrite sandbox registration.
+  CommandLine& command_line = *base::CommandLine::ForCurrentProcess();
+  command_line.AppendSwitchASCII(switches::kRegisterFontFiles,
+                                 base::WideToUTF8(font_path.value()));
+
   return true;
 }