Do more page load/unload checks in EmbedderTest.

- Keep track of pages in a single map when calling LoadPage(). It is
  simpler and performance is not crucial as the number of loaded pages
  is usually very small.
- Verify UnloadPage() is only called for loaded pages.
- Verify there are no loaded pages in TearDown().
- Verify RenderLoadedPage methods are only rendering loaded pages.
- Fix pages that are using FPDF_LoadPage() and FPDF_ClosePage() when
  they should be using LoadPage() and UnloadPage().
- Disallow calling LoadPage() for the same page number repeatedly. No
  caller does this and it makes verification in UnloadPage() harder.

Change-Id: I58878ea8ade21dde28f1bbebd3a3304ce677561d
Reviewed-on: https://pdfium-review.googlesource.com/25550
Reviewed-by: dsinclair <dsinclair@chromium.org>
Commit-Queue: Lei Zhang <thestig@chromium.org>

1 files changed, 3 insertions, 3 deletions

diff --git a/fpdfsdk/fpdf_structtree_embeddertest.cpp b/fpdfsdk/fpdf_structtree_embeddertest.cpp
index 7ca81f7b2e..b638cdc315 100644
--- a/fpdfsdk/fpdf_structtree_embeddertest.cpp
+++ b/fpdfsdk/fpdf_structtree_embeddertest.cpp
@@ -71,7 +71,7 @@ TEST_F(FPDFStructTreeEmbeddertest, GetAltText) {
   EXPECT_EQ(nullptr, ggchild_element);
 
   FPDF_StructTree_Close(struct_tree);
-  FPDF_ClosePage(page);
+  UnloadPage(page);
 }
 
 TEST_F(FPDFStructTreeEmbeddertest, GetMarkedContentID) {
@@ -87,7 +87,7 @@ TEST_F(FPDFStructTreeEmbeddertest, GetMarkedContentID) {
   EXPECT_EQ(0, FPDF_StructElement_GetMarkedContentID(element));
 
   FPDF_StructTree_Close(struct_tree);
-  FPDF_ClosePage(page);
+  UnloadPage(page);
 }
 
 TEST_F(FPDFStructTreeEmbeddertest, GetType) {
@@ -116,5 +116,5 @@ TEST_F(FPDFStructTreeEmbeddertest, GetType) {
             WideString::FromUTF16LE(buffer, FXSYS_len(kExpected)));
 
   FPDF_StructTree_Close(struct_tree);
-  FPDF_ClosePage(page);
+  UnloadPage(page);
 }