Add ability to log click events reaching PDFium

Adds in logging statement to related API methods and a build flag to
control enabling the feature. This is meant to be used in conjunction
with Chromium.

A developer can enable this flag, load a test PDF, and then click on
elements to determine appropriate coordinates for an .evt file.

BUG=pdfium:1057

Change-Id: I956c39f545297872a61affdb621a412b3c407ff5
Reviewed-on: https://pdfium-review.googlesource.com/34010
Reviewed-by: Tom Sepez <tsepez@chromium.org>
Reviewed-by: Henrique Nakashima <hnakashima@chromium.org>
Commit-Queue: Ryan Harrison <rharrison@chromium.org>

1 files changed, 4 insertions, 0 deletions

diff --git a/BUILD.gn b/BUILD.gn
index d88c1d621b..3422b81535 100644
--- a/BUILD.gn
+++ b/BUILD.gn
@@ -30,6 +30,10 @@ config("pdfium_common_config") {
     defines += [ "PDF_ENABLE_V8" ]
   }
 
+  if (pdf_enable_click_logging) {
+    defines += [ "PDF_ENABLE_CLICK_LOGGING" ]
+  }
+
   if (pdf_enable_xfa) {
     defines += [ "PDF_ENABLE_XFA" ]
     if (pdf_enable_xfa_bmp) {