Invalidate IPWL_FocusHandler and IPWL_Provider on destruction.

fpdfsdk/src/fpdfview_embeddertest.cpp

 // Copyright 2015 PDFium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include <limits>
 #include <string>
 
 #include "fpdfsdk/src/fpdfview_c_api_test.h"
 #include "public/fpdfview.h"
 #include "testing/embedder_test.h"
@@ skipping 178 matching lines @@
 }
 
 TEST_F(FPDFViewEmbeddertest, Crasher_452455) {
   EXPECT_TRUE(OpenDocument("bug_452455.pdf"));
   FPDF_PAGE page = LoadPage(0);
   EXPECT_NE(nullptr, page);
   UnloadPage(page);
 }
 
 TEST_F(FPDFViewEmbeddertest, Crasher_454695) {
-  // Document is damanged and can't be opened.
+  // Document is damaged and can't be opened.
   EXPECT_FALSE(OpenDocument("bug_454695.pdf"));
 }
 
+TEST_F(FPDFViewEmbeddertest, Crasher_572871) {
+  EXPECT_TRUE(OpenDocument("bug_572871.pdf"));
+}
+
 // The following tests pass if the document opens without infinite looping.
 TEST_F(FPDFViewEmbeddertest, Hang_298) {
   EXPECT_FALSE(OpenDocument("bug_298.pdf"));
 }
 
 // Test if the document opens without infinite looping.
 // Previously this test will hang in a loop inside LoadAllCrossRefV4. After
 // the fix, LoadAllCrossRefV4 will return false after detecting a cross
 // reference loop. Cross references will be rebuilt successfully.
 TEST_F(FPDFViewEmbeddertest, CrossRefV4Loop) {
   EXPECT_TRUE(OpenDocument("bug_xrefv4_loop.pdf"));
 }