Move fx_crypto.h and fpdf_text.h out of core/include.

This CL moves the two files and breaks fpdf_text.h apart into individual pieces.

R=tsepez@chromium.org

Review URL: https://codereview.chromium.org/1801973002 .
diff --git a/BUILD.gn b/BUILD.gn
index 2f51c21..d0de412 100644
--- a/BUILD.gn
+++ b/BUILD.gn
@@ -201,7 +201,7 @@
     "core/fdrm/crypto/fx_crypt.cpp",
     "core/fdrm/crypto/fx_crypt_aes.cpp",
     "core/fdrm/crypto/fx_crypt_sha.cpp",
-    "core/include/fdrm/fx_crypt.h",
+    "core/fdrm/crypto/include/fx_crypt.h",
   ]
   configs += [ ":pdfium_config" ]
 }
@@ -390,11 +390,13 @@
 static_library("fpdftext") {
   sources = [
     "core/fpdftext/fpdf_text_int.cpp",
+    "core/fpdftext/include/ipdf_linkextract.h",
+    "core/fpdftext/include/ipdf_textpage.h",
+    "core/fpdftext/include/ipdf_textpagefind.h",
     "core/fpdftext/text_int.h",
     "core/fpdftext/unicodenormalization.cpp",
     "core/fpdftext/unicodenormalizationdata.cpp",
     "core/fpdftext/unicodenormalizationdata.h",
-    "core/include/fpdftext/fpdf_text.h",
   ]
   configs += [ ":pdfium_config" ]
 }