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

pdf/pdfium/pdfium_engine.h

Index: pdf/pdfium/pdfium_engine.h
diff --git a/pdf/pdfium/pdfium_engine.h b/pdf/pdfium/pdfium_engine.h
index 6620c77cb6bad9313550bdb79835ac494e61afdb..60c41bc67c7cd667ed06cc23cfbfd8133ea73607 100644
--- a/pdf/pdfium/pdfium_engine.h
+++ b/pdf/pdfium/pdfium_engine.h
@@ -318,6 +318,11 @@ class PDFiumEngine : public PDFEngine,
       const PP_PrintSettings_Dev& print_settings);
   void SaveSelectedFormForPrint();
 
+  // Sets plugin's selected text to be selected text in form text field
+  // if available.
+  void SetFormSelectedText(const FPDF_FORMHANDLE& hHandle,
+                           const FPDF_PAGE& page);
+
   // Given a mouse event, returns which page and character location it's closest
   // to.
   PDFiumPage::Area GetCharIndex(const pp::MouseInputEvent& event,
@@ -440,6 +445,9 @@ class PDFiumEngine : public PDFEngine,
   // Setting selection status of document.
   void SetSelecting(bool selecting);
 
+  // Sets status of whether or not focus is in form field text field.

[Lei Zhang, 2017/06/14 07:07:03]

As mentioned in the PDFium-side CL, how about just "form text field" ? Ditto on
line 657.

[drgage, 2017/06/14 22:53:40]

Done.

+  void SetInFormTextField(bool in_form_text_field);
+
   bool PageIndexInBounds(int index) const;
 
   void ScheduleTouchTimer(const pp::TouchInputEvent& event);
@@ -646,6 +654,9 @@ class PDFiumEngine : public PDFEngine,
   // True if we're in the middle of selection.
   bool selecting_;
 
+  // True if focus is on form field text field.
+  bool in_form_text_field_;
+
   MouseDownState mouse_down_state_;
 
   // Used for searching.