Add functionality for copying text within form text fields and form combobox text fields

pdf/pdfium/pdfium_page.cc

Index: pdf/pdfium/pdfium_page.cc
diff --git a/pdf/pdfium/pdfium_page.cc b/pdf/pdfium/pdfium_page.cc
index 7d85d36aa315e5447995c168c4e4a86caf7a9d5d..860767a5f422618efd66314ad8673e034f0b196c 100644
--- a/pdf/pdfium/pdfium_page.cc
+++ b/pdf/pdfium/pdfium_page.cc
@@ -264,7 +264,7 @@ PDFiumPage::Area PDFiumPage::GetCharIndex(const pp::Point& point,
     DCHECK_NE(control_z_order, link_z_order);
     if (control_z_order > link_z_order) {
       *form_type = control;
-      return PDFiumPage::NONSELECTABLE_AREA;
+      return FormTypeToArea(*form_type);
     }
 
     // We don't handle all possible link types of the PDF. For example,
@@ -283,7 +283,7 @@ PDFiumPage::Area PDFiumPage::GetCharIndex(const pp::Point& point,
       return area;
   } else if (control > FPDF_FORMFIELD_UNKNOWN) {
     *form_type = control;
-    return PDFiumPage::NONSELECTABLE_AREA;
+    return FormTypeToArea(*form_type);
   }
 
   if (rv < 0)
@@ -292,6 +292,17 @@ PDFiumPage::Area PDFiumPage::GetCharIndex(const pp::Point& point,
   return GetLink(*char_index, target) != -1 ? WEBLINK_AREA : TEXT_AREA;
 }
 
+// static
+PDFiumPage::Area PDFiumPage::FormTypeToArea(int form_type) {
+  switch (form_type) {
+    case FPDF_FORMFIELD_COMBOBOX:
+    case FPDF_FORMFIELD_TEXTFIELD:
+      return PDFiumPage::FORM_TEXT_AREA;
+    default:
+      return PDFiumPage::NONSELECTABLE_AREA;
+  }
+}
+
 base::char16 PDFiumPage::GetCharAtIndex(int index) {
   if (!available_)
     return L'\0';