Fix for the font files being maped multiple times (Fontconfig).

content/common/font_config_ipc_linux.h

Index: content/common/font_config_ipc_linux.h
diff --git a/content/common/font_config_ipc_linux.h b/content/common/font_config_ipc_linux.h
index c5cf80f72744dac30632e84bd43563e9fa94472d..f6501de698d53c50ecc101ee2406a122797d4d73 100644
--- a/content/common/font_config_ipc_linux.h
+++ b/content/common/font_config_ipc_linux.h
@@ -6,6 +6,8 @@
 #define CONTENT_COMMON_FONT_CONFIG_IPC_LINUX_H_
 
 #include "base/compiler_specific.h"
+#include "base/containers/hash_tables.h"
+#include "base/memory/weak_ptr.h"
 #include "third_party/skia/include/ports/SkFontConfigInterface.h"
 
 #include <string>
@@ -37,7 +39,14 @@ class FontConfigIPC : public SkFontConfigInterface {
   };
 
  private:
+  class FontMemoryStream;
+
+  FontMemoryStream* StreamFromFD(int fd);
+  void PurgeFontStreamCache();
+
   const int fd_;
+  // Maps font identity ID to the cached memory stream with font data:
+  base::hash_map<uint32_t, base::WeakPtr<FontMemoryStream>> font_stream_cache_;
 };
 
 }  // namespace content