Add a second unsafe ES3 API in command buffer.

gpu/command_buffer/common/gles2_cmd_format_test_autogen.h

Index: gpu/command_buffer/common/gles2_cmd_format_test_autogen.h
diff --git a/gpu/command_buffer/common/gles2_cmd_format_test_autogen.h b/gpu/command_buffer/common/gles2_cmd_format_test_autogen.h
index df4e94f8cd3c74764e908c5012ccc8a628cfc201..cb64dd1a2be27445aaea34adfe0782f42ae8278a 100644
--- a/gpu/command_buffer/common/gles2_cmd_format_test_autogen.h
+++ b/gpu/command_buffer/common/gles2_cmd_format_test_autogen.h
@@ -366,6 +366,23 @@ TEST_F(GLES2FormatTest, CompressedTexSubImage2D) {
   CheckBytesWrittenMatchesExpectedSize(next_cmd, sizeof(cmd));
 }
 
+TEST_F(GLES2FormatTest, CopyBufferSubData) {
+  cmds::CopyBufferSubData& cmd = *GetBufferAs<cmds::CopyBufferSubData>();
+  void* next_cmd =
+      cmd.Set(&cmd, static_cast<GLenum>(11), static_cast<GLenum>(12),
+              static_cast<GLintptr>(13), static_cast<GLintptr>(14),
+              static_cast<GLsizeiptr>(15));
+  EXPECT_EQ(static_cast<uint32_t>(cmds::CopyBufferSubData::kCmdId),
+            cmd.header.command);
+  EXPECT_EQ(sizeof(cmd), cmd.header.size * 4u);
+  EXPECT_EQ(static_cast<GLenum>(11), cmd.readtarget);
+  EXPECT_EQ(static_cast<GLenum>(12), cmd.writetarget);
+  EXPECT_EQ(static_cast<GLintptr>(13), cmd.readoffset);
+  EXPECT_EQ(static_cast<GLintptr>(14), cmd.writeoffset);
+  EXPECT_EQ(static_cast<GLsizeiptr>(15), cmd.size);
+  CheckBytesWrittenMatchesExpectedSize(next_cmd, sizeof(cmd));
+}
+
 TEST_F(GLES2FormatTest, CopyTexImage2D) {
   cmds::CopyTexImage2D& cmd = *GetBufferAs<cmds::CopyTexImage2D>();
   void* next_cmd = cmd.Set(&cmd, static_cast<GLenum>(11),