Basic APIs and tests for extracting annotations

1. Added API for extracting annotation properties:
  * Added testing flag "--annot" that outputs the annotation properties
into a .txt file.
  * Added two embedder tests covering all the API functions.

Bug=pdfium:737
Change-Id: I95943a9b2b3d5d431bc8a74a31b27b4f4b521026
Reviewed-on: https://pdfium-review.googlesource.com/6092
Commit-Queue: Jane Liu <janeliulwq@google.com>
Reviewed-by: Lei Zhang <thestig@chromium.org>
Reviewed-by: dsinclair <dsinclair@chromium.org>
diff --git a/fpdfsdk/fpdfview_c_api_test.c b/fpdfsdk/fpdfview_c_api_test.c
index 37f1d91..5a65fc4 100644
--- a/fpdfsdk/fpdfview_c_api_test.c
+++ b/fpdfsdk/fpdfview_c_api_test.c
@@ -9,6 +9,7 @@
 
 #include "fpdfsdk/fpdfview_c_api_test.h"
 
+#include "public/fpdf_annot.h"
 #include "public/fpdf_dataavail.h"
 #include "public/fpdf_doc.h"
 #include "public/fpdf_edit.h"
@@ -33,6 +34,15 @@
 
 // Function to call from gtest harness to ensure linker resolution.
 int CheckPDFiumCApi() {
+    //fpdf_annot.h
+    CHK(FPDFPage_GetAnnotCount);
+    CHK(FPDFPage_GetAnnot);
+    CHK(FPDFAnnot_GetSubtype);
+    CHK(FPDFAnnot_GetColor);
+    CHK(FPDFAnnot_GetAttachmentPoints);
+    CHK(FPDFAnnot_GetRect);
+    CHK(FPDFAnnot_GetText);
+
     // fpdf_dataavail.h
     CHK(FPDFAvail_Create);
     CHK(FPDFAvail_Destroy);