CPDF_Document::LoadPattern() and friends always have a valid matrix.

BUILD.gn

 # Copyright 2016 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 import("//build_overrides/v8.gni")
 import("//testing/test.gni")
 import("pdfium.gni")
 
 config("pdfium_config") {
   cflags = []
@@ skipping 365 matching lines @@
     "core/fpdfapi/fpdf_page/cpdf_textstate.cpp",
     "core/fpdfapi/fpdf_page/cpdf_textstate.h",
     "core/fpdfapi/fpdf_page/cpdf_textstatedata.cpp",
     "core/fpdfapi/fpdf_page/cpdf_tilingpattern.cpp",
     "core/fpdfapi/fpdf_page/cpdf_tilingpattern.h",
     "core/fpdfapi/fpdf_page/fpdf_page_colors.cpp",
     "core/fpdfapi/fpdf_page/fpdf_page_doc.cpp",
     "core/fpdfapi/fpdf_page/fpdf_page_func.cpp",
     "core/fpdfapi/fpdf_page/fpdf_page_parser.cpp",
     "core/fpdfapi/fpdf_page/fpdf_page_parser_old.cpp",
-    "core/fpdfapi/fpdf_page/fpdf_page_pattern.cpp",
     "core/fpdfapi/fpdf_page/include/cpdf_clippath.h",
     "core/fpdfapi/fpdf_page/include/cpdf_color.h",
     "core/fpdfapi/fpdf_page/include/cpdf_colorspace.h",
     "core/fpdfapi/fpdf_page/include/cpdf_form.h",
     "core/fpdfapi/fpdf_page/include/cpdf_formobject.h",
     "core/fpdfapi/fpdf_page/include/cpdf_generalstate.h",
     "core/fpdfapi/fpdf_page/include/cpdf_generalstatedata.h",
     "core/fpdfapi/fpdf_page/include/cpdf_image.h",
     "core/fpdfapi/fpdf_page/include/cpdf_imageobject.h",
     "core/fpdfapi/fpdf_page/include/cpdf_page.h",
@@ skipping 1310 matching lines @@
 }
 
 if (pdf_is_standalone) {
   source_set("samples") {
     testonly = true
     deps = [
       "//samples",
     ]
   }
 }