Get rid of IPDF_DataAvail.

BUILD.gn

Index: BUILD.gn
diff --git a/BUILD.gn b/BUILD.gn
index 59215c1dd2b748767cd36bb3cc4d0e31ede083b8..98027d049271d5162259f53ed6fae55b475b2193 100644
--- a/BUILD.gn
+++ b/BUILD.gn
@@ -413,7 +413,6 @@ static_library("fpdfapi") {
     "core/fpdfapi/fpdf_parser/cpdf_crypto_handler.cpp",
     "core/fpdfapi/fpdf_parser/cpdf_crypto_handler.h",
     "core/fpdfapi/fpdf_parser/cpdf_data_avail.cpp",
-    "core/fpdfapi/fpdf_parser/cpdf_data_avail.h",
     "core/fpdfapi/fpdf_parser/cpdf_dictionary.cpp",
     "core/fpdfapi/fpdf_parser/cpdf_document.cpp",
     "core/fpdfapi/fpdf_parser/cpdf_hint_tables.cpp",
@@ -439,6 +438,7 @@ static_library("fpdfapi") {
     "core/fpdfapi/fpdf_parser/fpdf_parser_utility.h",
     "core/fpdfapi/fpdf_parser/include/cfdf_document.h",
     "core/fpdfapi/fpdf_parser/include/cpdf_array.h",
+    "core/fpdfapi/fpdf_parser/include/cpdf_data_avail.h",
     "core/fpdfapi/fpdf_parser/include/cpdf_dictionary.h",
     "core/fpdfapi/fpdf_parser/include/cpdf_document.h",
     "core/fpdfapi/fpdf_parser/include/cpdf_indirect_object_holder.h",
@@ -452,7 +452,6 @@ static_library("fpdfapi") {
     "core/fpdfapi/fpdf_parser/include/cpdf_stream_acc.h",
     "core/fpdfapi/fpdf_parser/include/cpdf_string.h",
     "core/fpdfapi/fpdf_parser/include/fpdf_parser_decode.h",
-    "core/fpdfapi/fpdf_parser/include/ipdf_data_avail.h",
     "core/fpdfapi/fpdf_render/cpdf_pagerendercache.h",
     "core/fpdfapi/fpdf_render/fpdf_render.cpp",
     "core/fpdfapi/fpdf_render/fpdf_render_cache.cpp",