Fix another discrepancy in text selection between PDF and HTML forms.

pdf/pdfium/pdfium_engine.cc

 // 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.
 
 #include "pdf/pdfium/pdfium_engine.h"
 
 #include <math.h>
 #include <stddef.h>
 #include <stdint.h>
 
@@ skipping 1635 matching lines @@
   base::string16 selected_form_text16;
   PDFiumAPIStringBufferSizeInBytesAdapter<base::string16> string_adapter(
       &selected_form_text16, form_sel_text_len, false);
   string_adapter.Close(FORM_GetSelectedText(
       form_handle, page, string_adapter.GetData(), form_sel_text_len));
 
   // Update previous and current selections, then compare them to check if
   // selection has changed. If so, set plugin text selection.
   std::string selected_form_text = selected_form_text_;
   selected_form_text_ = base::UTF16ToUTF8(selected_form_text16);
-  if (selected_form_text != selected_form_text_)
+  if (selected_form_text != selected_form_text_) {
+    DCHECK(in_form_text_area_);
     pp::PDF::SetSelectedText(GetPluginInstance(), selected_form_text_.c_str());
+  }
 }
 
 void PDFiumEngine::PrintEnd() {
   FORM_DoDocumentAAction(form_, FPDFDOC_AACTION_DP);
 }
 
 PDFiumPage::Area PDFiumEngine::GetCharIndex(const pp::MouseInputEvent& event,
                                             int* page_index,
                                             int* char_index,
                                             int* form_type,
@@ skipping 50 matching lines @@
     return true;
   }
 
   if (event.GetButton() != PP_INPUTEVENT_MOUSEBUTTON_LEFT &&
       event.GetButton() != PP_INPUTEVENT_MOUSEBUTTON_MIDDLE) {
     return false;
   }
 
   SetMouseLeftButtonDown(event.GetButton() == PP_INPUTEVENT_MOUSEBUTTON_LEFT);
 
-  SelectionChangeInvalidator selection_invalidator(this);
+  auto selection_invalidator =
+      base::MakeUnique<SelectionChangeInvalidator>(this);
   selection_.clear();
 
   int page_index = -1;
   int char_index = -1;
   int form_type = FPDF_FORMFIELD_UNKNOWN;
   PDFiumPage::LinkTarget target;
   PDFiumPage::Area area =
       GetCharIndex(event, &page_index, &char_index, &form_type, &target);
   mouse_down_state_.Set(area, target);
 
   // Decide whether to open link or not based on user action in mouse up and
   // mouse move events.
   if (area == PDFiumPage::WEBLINK_AREA || area == PDFiumPage::DOCLINK_AREA)
     return true;
 
   // Prevent middle mouse button from selecting texts.
   if (event.GetButton() == PP_INPUTEVENT_MOUSEBUTTON_MIDDLE)
     return false;
 
   if (page_index != -1) {
     last_page_mouse_down_ = page_index;
     double page_x, page_y;
     pp::Point point = event.GetPosition();
     DeviceToPage(page_index, point.x(), point.y(), &page_x, &page_y);
 
     FORM_OnLButtonDown(form_, pages_[page_index]->GetPage(), 0, page_x, page_y);
     if (form_type > FPDF_FORMFIELD_UNKNOWN) {  // returns -1 sometimes...
       mouse_down_state_.Set(PDFiumPage::FormTypeToArea(form_type), target);
 
+      // Destroy SelectionChangeInvalidator object before SetInFormTextArea()
+      // changes plugin's focus to be in form text area. This way, regular text
+      // selection can be cleared when a user clicks into a form text area
+      // because the pp::PDF::SetSelectedText() call in
+      // ~SelectionChangeInvalidator() still goes to the Mimehandler
+      // (not the Renderer).
+      selection_invalidator.reset();
+
       bool is_valid_control = (form_type == FPDF_FORMFIELD_TEXTFIELD ||
                                form_type == FPDF_FORMFIELD_COMBOBOX);
 
 // TODO(bug_62400): figure out selection and copying
 // for XFA fields
 #if defined(PDF_ENABLE_XFA)
       is_valid_control |= (form_type == FPDF_FORMFIELD_XFA);
 #endif
       SetInFormTextArea(is_valid_control);
       return true;  // Return now before we get into the selection code.
@@ skipping 1808 matching lines @@
     *region = nullptr;
     return;
   }
 
   buffer += location.y() * (*stride);
   buffer += (location.x() + page_offset_.x()) * 4;
   *region = buffer;
 }
 
 void PDFiumEngine::OnSelectionChanged() {
+  DCHECK(!in_form_text_area_);
   pp::PDF::SetSelectedText(GetPluginInstance(), GetSelectedText().c_str());
 }
 
 void PDFiumEngine::RotateInternal() {
   // Store the current find index so that we can resume finding at that
   // particular index after we have recomputed the find results.
   std::string current_find_text = current_find_text_;
   if (current_find_index_.valid())
     resume_find_index_.SetIndex(current_find_index_.GetIndex());
   else
@@ skipping 18 matching lines @@
 }
 
 void PDFiumEngine::SetSelecting(bool selecting) {
   bool was_selecting = selecting_;
   selecting_ = selecting;
   if (selecting_ != was_selecting)
     client_->IsSelectingChanged(selecting);
 }
 
 void PDFiumEngine::SetInFormTextArea(bool in_form_text_area) {
+  // If focus was previously in form text area, clear form text selection.
+  // Clearing needs to be done before changing focus to ensure the correct
+  // observer is notified of the change in selection. When |in_form_text_area_|
+  // is true, this is the Renderer. After it flips, the MimeHandler is notified.
+  if (in_form_text_area_)
+    pp::PDF::SetSelectedText(GetPluginInstance(), "");
+
   client_->FormTextFieldFocusChange(in_form_text_area);
   in_form_text_area_ = in_form_text_area;
 }
 
 void PDFiumEngine::SetMouseLeftButtonDown(bool is_mouse_left_button_down) {
   mouse_left_button_down_ = is_mouse_left_button_down;
 }
 
 void PDFiumEngine::ScheduleTouchTimer(const pp::TouchInputEvent& evt) {
   touch_timers_[++next_touch_timer_id_] = evt;
@@ skipping 577 matching lines @@
   FPDF_DOCUMENT doc =
       FPDF_LoadMemDocument(pdf_buffer, pdf_buffer_size, nullptr);
   if (!doc)
     return false;
   bool success = FPDF_GetPageSizeByIndex(doc, page_number, width, height) != 0;
   FPDF_CloseDocument(doc);
   return success;
 }
 
 }  // namespace chrome_pdf