Add FPDFPageObj_GetStrokeWidth() API

It was already possible to set the stroke width of a page object, this
is the other direction.

Change-Id: I5c4681b232768fc928bc7a169f223877284d4812
Reviewed-on: https://pdfium-review.googlesource.com/32770
Reviewed-by: dsinclair <dsinclair@chromium.org>
Commit-Queue: dsinclair <dsinclair@chromium.org>
diff --git a/fpdfsdk/fpdf_editpage.cpp b/fpdfsdk/fpdf_editpage.cpp
index 1a9198b..ea4659f 100644
--- a/fpdfsdk/fpdf_editpage.cpp
+++ b/fpdfsdk/fpdf_editpage.cpp
@@ -592,6 +592,16 @@
 }
 
 FPDF_EXPORT FPDF_BOOL FPDF_CALLCONV
+FPDFPageObj_GetStrokeWidth(FPDF_PAGEOBJECT page_object, float* width) {
+  auto* pPageObj = CPDFPageObjectFromFPDFPageObject(page_object);
+  if (!pPageObj || !width)
+    return false;
+
+  *width = pPageObj->m_GraphState.GetLineWidth();
+  return true;
+}
+
+FPDF_EXPORT FPDF_BOOL FPDF_CALLCONV
 FPDFPageObj_SetLineJoin(FPDF_PAGEOBJECT page_object, int line_join) {
   if (!page_object)
     return false;