Fix discrepancies in form text selection between PDF and HTML forms.

pdf/pdfium/pdfium_engine.h

 // Copyright (c) 2012 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.
 
 #ifndef PDF_PDFIUM_PDFIUM_ENGINE_H_
 #define PDF_PDFIUM_PDFIUM_ENGINE_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
@@ skipping 431 matching lines @@
   void RotateInternal();
 
   // Sets text selection status of document. This does not include text
   // within form text fields.
   void SetSelecting(bool selecting);
 
   // Sets whether or not focus is in form text field or form combobox text
   // field.
   void SetInFormTextArea(bool in_form_text_area);
 
+  // Sets whether or not left mouse button is currently being held down.
+  void SetMouseHeldDown(bool mouse_held_down);
+
   bool PageIndexInBounds(int index) const;
 
   void ScheduleTouchTimer(const pp::TouchInputEvent& event);
   void KillTouchTimer(int timer_id);
   void HandleLongPress(const pp::TouchInputEvent& event);
 
   // FPDF_FORMFILLINFO callbacks.
   static void Form_Invalidate(FPDF_FORMFILLINFO* param,
                               FPDF_PAGE page,
                               double left,
@@ skipping 180 matching lines @@
 
   // The indexes of the pages pending download.
   std::vector<int> pending_pages_;
 
   // During handling of input events we don't want to unload any pages in
   // callbacks to us from PDFium, since the current page can change while PDFium
   // code still has a pointer to it.
   bool defer_page_unload_;
   std::vector<int> deferred_page_unloads_;
 
-  // Used for text selection, but does not include text within form text fields.
+  // Used for text selection, but does not include text within form text areas.
   // There could be more than one range if selection spans more than one page.
   std::vector<PDFiumRange> selection_;
   // True if we're in the middle of text selection.
   bool selecting_;
 
+  // Used for selection of text within form text areas (text fields and combo
+  // box text fields). Represents the currently selected text.
+  std::string selected_form_text_;
+
+  // Used for selection of text within form text areas (text fields and combo
+  // box text fields). Represents the previously selected text.
+  std::string old_selected_form_text_;
+
   // True if focus is in form text field or form combobox text field.
   bool in_form_text_area_;
 
+  // True if left mouse button is currently being held down.
+  bool mouse_held_down_;

[Lei Zhang, 2017/06/29 02:52:46]

Do we need |mouse_held_down_| if we already have |selecting_| on line 659 above?

[drgage, 2017/06/29 17:49:59]

The reason I added |mouse_held_down_| is because the way |selecting_| is
currently being used is for text selection only (i.e. it corresponds to the
|selection_| variable). If you see how it is used in pdfium_engine.cc, it's set
to true in PDFiumEngine::OnSingleClick(), which is only called in
PDFiumEngine::OnMouseDown() in PDFiumPage::TEXT_AREAs. Also, much of what needs
to happen for form text area selection in PDFiumEngine::OnMouseMove() can only
happen if |selecting_| is set to false.

If you think it would make more sense to try to change the way |selecting_| is
being used as opposed to adding another variable, I can look into doing that.

+
   MouseDownState mouse_down_state_;
 
   // Used for searching.
   std::vector<PDFiumRange> find_results_;
   // Which page to search next.
   int next_page_to_search_;
   // Where to stop searching.
   int last_page_to_search_;
   int last_character_index_to_search_;  // -1 if search until end of page.
   // Which result the user has currently selected.
@@ skipping 139 matching lines @@
   bool GetPDFPageSizeByIndex(const void* pdf_buffer,
                              int pdf_buffer_size,
                              int page_number,
                              double* width,
                              double* height) override;
 };
 
 }  // namespace chrome_pdf
 
 #endif  // PDF_PDFIUM_PDFIUM_ENGINE_H_