[M53] Bound total pixels in JBig2 images to avoid overflows later.

BUILD.gn

Index: BUILD.gn
diff --git a/BUILD.gn b/BUILD.gn
index 10fe5df33239630ea5804f82c2566b48e3ff38b6..fd34c49c003104968b8048fd162d1e929a731ffc 100644
--- a/BUILD.gn
+++ b/BUILD.gn
@@ -1463,6 +1463,7 @@ test("pdfium_unittests") {
     "core/fpdfdoc/doc_basic_unittest.cpp",
     "core/fpdftext/fpdf_text_int_unittest.cpp",
     "core/fxcodec/codec/fx_codec_jpx_unittest.cpp",
+    "core/fxcodec/jbig2/JBig2_Image_unittest.cpp",
     "core/fxcrt/cfx_retain_ptr_unittest.cpp",
     "core/fxcrt/fx_basic_bstring_unittest.cpp",
     "core/fxcrt/fx_basic_gcc_unittest.cpp",