Add pdf layer code for PDFium XFA module

pdf/BUILD.gn

 # Copyright 2014 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 pdf_engine = 0  # 0 PDFium
+pdf_use_xfa = 0
 
 # TODO(GYP) need support for loadable modules
 shared_library("pdf") {
   sources = [
     "button.h",
     "button.cc",
     "chunk_stream.h",
     "chunk_stream.cc",
     "control.h",
     "control.cc",
@@ skipping 42 matching lines @@
       "pdfium/pdfium_mem_buffer_file_read.h",
       "pdfium/pdfium_mem_buffer_file_write.cc",
       "pdfium/pdfium_mem_buffer_file_write.h",
       "pdfium/pdfium_page.cc",
       "pdfium/pdfium_page.h",
       "pdfium/pdfium_range.cc",
       "pdfium/pdfium_range.h",
     ]
   }
 
+  if(pdf_use_xfa == 1) {

[Lei Zhang, 2014/11/06 04:08:08]

nit: space after if

+    defines += [ "_PDF_USE_XFA_" ]

[Lei Zhang, 2014/11/06 04:08:08]

You need to start with:

defines = []

after sources = [ ... ]

and also change the "defines =" below to "defines +="

[Bo Xu, 2014/11/06 05:43:51]

Done.

[Lei Zhang, 2014/11/06 19:15:29]

You need to write it like:

defines = []
if (condition1) {
  defines += [d1]
}
if (condition2) {
 ...
}

As is, "defines" isn't defined on non-Windows platforms to start, and defines +=
[ "PDF_USE_XFA" ] won't work.

+  }
+
   if (is_win) {
     defines = [ "COMPILE_CONTENT_STATICALLY" ]
     cflags = [ "/wd4267" ]  # TODO(jschuh) size_t to int truncations.
   }
 
   if (is_mac) {
     # TODO(GYP)
     #'mac_bundle': 1,
     #'product_name': 'PDF',
     #'product_extension': 'plugin',
@@ skipping 12 matching lines @@
 
   deps = [
     "//base",
     "//net",
     "//ppapi:ppapi_cpp",
     "//third_party/pdfium",
   ]
 }
 
 # TODO(GYP) pdf_linux_symbols target.