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

pdf/pdfium/pdfium_engine.cc

Index: pdf/pdfium/pdfium_engine.cc
diff --git a/pdf/pdfium/pdfium_engine.cc b/pdf/pdfium/pdfium_engine.cc
index afc8b71633bcd2bbab24880da6b033316bfe63a9..2c38a30cf4a03ee069087a72255cad44cabf00aa 100644
--- a/pdf/pdfium/pdfium_engine.cc
+++ b/pdf/pdfium/pdfium_engine.cc
@@ -1625,6 +1625,28 @@ void PDFiumEngine::FitContentsToPrintableAreaIfRequired(
 void PDFiumEngine::SaveSelectedFormForPrint() {
   FORM_ForceToKillFocus(form_);
   client_->FormTextFieldFocusChange(false);
+  SetInFormTextField(false);
+}
+
+void PDFiumEngine::SetFormSelectedText(const FPDF_FORMHANDLE& hHandle,
+                                       const FPDF_PAGE& page) {
+  size_t form_sel_text_len = FORM_GetSelectedText(hHandle, page, nullptr, 0);
+
+  // Initial length = 2 (not 0) because text is CFX_WideString and
+  // sentinel char is included in count.
+  if (form_sel_text_len <= 2)
+    return;
+
+  base::string16 selected_form_text16;
+  PDFiumAPIStringBufferSizeInBytesAdapter<base::string16> string_adapter(
+      &selected_form_text16, form_sel_text_len, false);
+  string_adapter.Close(FORM_GetSelectedText(
+      hHandle, page, string_adapter.GetData(), form_sel_text_len));
+
+  std::string selected_form_text = UTF16ToUTF8(selected_form_text16);
+  if (!selected_form_text.empty()) {
+    pp::PDF::SetSelectedText(GetPluginInstance(), selected_form_text.c_str());
+  }
 }
 
 void PDFiumEngine::PrintEnd() {
@@ -1721,18 +1743,29 @@ bool PDFiumEngine::OnMouseDown(const pp::MouseInputEvent& event) {
 
     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::NONSELECTABLE_AREA, target);
+      mouse_down_state_.Set(form_type == FPDF_FORMFIELD_TEXTFIELD
+                                ? PDFiumPage::FORM_TEXT_AREA
+                                : PDFiumPage::NONSELECTABLE_AREA,
+                            target);
+
       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
+
+      // TODO(drgage): implement copying for comboboxes
       client_->FormTextFieldFocusChange(is_valid_control);
+      SetInFormTextField(is_valid_control);
       return true;  // Return now before we get into the selection code.
     }
   }
 
   client_->FormTextFieldFocusChange(false);
+  SetInFormTextField(false);
 
   if (area != PDFiumPage::TEXT_AREA)
     return true;  // Return true so WebKit doesn't do its own highlighting.
@@ -1808,11 +1841,13 @@ bool PDFiumEngine::OnMouseUp(const pp::MouseInputEvent& event) {
 
       client_->NavigateTo(target.url, disposition);
       client_->FormTextFieldFocusChange(false);
+      SetInFormTextField(false);
       return true;
     }
     if (area == PDFiumPage::DOCLINK_AREA) {
       client_->ScrollToPage(target.page);
       client_->FormTextFieldFocusChange(false);
+      SetInFormTextField(false);
       return true;
     }
   }
@@ -1828,6 +1863,10 @@ bool PDFiumEngine::OnMouseUp(const pp::MouseInputEvent& event) {
     FORM_OnLButtonUp(form_, pages_[page_index]->GetPage(), 0, page_x, page_y);
   }
 
+  if (area == PDFiumPage::FORM_TEXT_AREA) {
+    SetFormSelectedText(form_, pages_[last_page_mouse_down_]->GetPage());
+  }
+
   if (!selecting_)
     return false;
 
@@ -1859,6 +1898,7 @@ bool PDFiumEngine::OnMouseMove(const pp::MouseInputEvent& event) {
         cursor = PP_CURSORTYPE_HAND;
         break;
       case PDFiumPage::NONSELECTABLE_AREA:
+      case PDFiumPage::FORM_TEXT_AREA:
       default:
         switch (form_type) {
           case FPDF_FORMFIELD_PUSHBUTTON:
@@ -1992,6 +2032,19 @@ bool PDFiumEngine::OnKeyUp(const pp::KeyboardInputEvent& event) {
   if (last_page_mouse_down_ == -1)
     return false;
 
+  if (in_form_text_field_) {
+    if (event.GetKeyCode() == ui::VKEY_SHIFT)
+      SetFormSelectedText(form_, pages_[last_page_mouse_down_]->GetPage());
+    else {
+      uint32_t modifiers = event.GetModifiers();

[Lei Zhang, 2017/06/16 21:34:53]

Try to declare variables as close to where they are used, within the right
scope. In this case, maybe even just get rid of the variable since it'll still
fit on 1 line.

[drgage, 2017/06/16 23:15:04]

Done.

+
+      // If a key other than shift is released while shift is not also
+      // being held down, selection of form field text should be invalidated.
+      if (modifiers & ~PP_INPUTEVENT_MODIFIER_SHIFTKEY)
+        SelectionChangeInvalidator selection_invalidator(this);

[Lei Zhang, 2017/06/16 21:34:53]

SelectionChangeInvalidator seems to do a lot of work internally. Do you really
it to do all that work here?

[drgage, 2017/06/16 23:15:04]

Done.

+    }
+  }
+
   return !!FORM_OnKeyUp(form_, pages_[last_page_mouse_down_]->GetPage(),
                         event.GetKeyCode(), event.GetModifiers());
 }
@@ -3553,6 +3606,10 @@ void PDFiumEngine::SetSelecting(bool selecting) {
     client_->IsSelectingChanged(selecting);
 }
 
+void PDFiumEngine::SetInFormTextField(bool in_form_text_field) {
+  in_form_text_field_ = in_form_text_field;
+}
+
 void PDFiumEngine::ScheduleTouchTimer(const pp::TouchInputEvent& evt) {
   touch_timers_[++next_touch_timer_id_] = evt;
   client_->ScheduleTouchTimerCallback(next_touch_timer_id_,