Index: chromium/third_party/angle/gni/angle.gni
===================================================================
--- chromium/third_party/angle/gni/angle.gni
+++ chromium/third_party/angle/gni/angle.gni
@@ -97,7 +97,8 @@ declare_args() {
 
   if (current_cpu == "arm64" || current_cpu == "x64" ||
       current_cpu == "mips64el" || current_cpu == "s390x" ||
-      current_cpu == "ppc64" || current_cpu == "loong64") {
+      current_cpu == "ppc64" || current_cpu == "loong64" ||
+      current_cpu == "riscv64") {
     angle_64bit_current_cpu = true
   } else if (current_cpu == "arm" || current_cpu == "x86" ||
              current_cpu == "mipsel" || current_cpu == "s390" ||
Index: chromium/third_party/angle/src/common/platform.h
===================================================================
--- chromium/third_party/angle/src/common/platform.h
+++ chromium/third_party/angle/src/common/platform.h
@@ -102,7 +102,7 @@
 #endif
 
 // Mips and arm devices need to include stddef for size_t.
-#if defined(__mips__) || defined(__arm__) || defined(__aarch64__)
+#if defined(__mips__) || defined(__arm__) || defined(__aarch64__) || defined(__riscv)
 #    include <stddef.h>
 #endif