Improve focused form field tracking in the PDF Viewer.

Instead of just determining if a text form field area has focus or not,
distinguish between text form field, non-text form field, and no form
field.

With this information, the PDF plugin can send "formFocusChange"
messages to the PDF UI with a focused value of true for non-text form
fields. The PDF UI can then avoid scrolling to correctly handle keyboard
shortcuts when non-text form fields are in focus.

Bug: 1266637
Change-Id: I39910d38dff16d3f4dea727899991ee91eba6f31
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3261665
Commit-Queue: Lei Zhang <thestig@chromium.org>
Reviewed-by: Daniel Hosseinian <dhoss@chromium.org>
Cr-Commit-Position: refs/heads/main@{#938357}

pdf/pdf_engine.h

@@ -102,6 +102,15 @@ class PDFEngine {
   // Maximum number of parameters a nameddest view can contain.
   static constexpr size_t kMaxViewParams = 4;
 
+  enum class FocusFieldType {
+    // Focus is not on any form field.
+    kNoFocus,
+    // Focus is on a form text field or form combobox text field.
+    kText,
+    // Focus is on a non-text field.
+    kNonText,
+  };
+
   // Named destination in a document.
   struct NamedDestination {
     // 0-based page number.
@@ -254,8 +263,8 @@ class PDFEngine {
     // Notifies the client about document load progress.
     virtual void DocumentLoadProgress(uint32_t available, uint32_t doc_size) {}
 
-    // Notifies the client about focus changes for form text fields.
-    virtual void FormTextFieldFocusChange(bool in_focus) {}
+    // Notifies the client about focus changes for form fields.
+    virtual void FormFieldFocusChange(FocusFieldType type) {}
 
     // Returns true if the plugin has been opened within print preview.
     virtual bool IsPrintPreview() const = 0;

pdf/pdf_view_plugin_base.cc

@@ -423,7 +423,7 @@ void PdfViewPluginBase::DocumentLoadComplete() {
   RecordDocumentMetrics();
 
   // Clear the focus state for on-screen keyboards.
-  FormTextFieldFocusChange(false);
+  FormFieldFocusChange(PDFEngine::FocusFieldType::kNoFocus);
 
   if (IsPrintPreview())
     OnPrintPreviewLoaded();
@@ -496,13 +496,13 @@ void PdfViewPluginBase::DocumentLoadProgress(uint32_t available,
   SendLoadingProgress(progress);
 }
 
-void PdfViewPluginBase::FormTextFieldFocusChange(bool in_focus) {
+void PdfViewPluginBase::FormFieldFocusChange(PDFEngine::FocusFieldType type) {
   base::Value message(base::Value::Type::DICTIONARY);
   message.SetStringKey("type", "formFocusChange");
-  message.SetBoolKey("focused", in_focus);
+  message.SetBoolKey("focused", type != PDFEngine::FocusFieldType::kNoFocus);
   SendMessage(std::move(message));
 
-  SetFormTextFieldInFocus(in_focus);
+  SetFormTextFieldInFocus(type == PDFEngine::FocusFieldType::kText);
 }
 
 bool PdfViewPluginBase::IsPrintPreview() const {

pdf/pdf_view_plugin_base.h

@@ -131,7 +131,7 @@ class PdfViewPluginBase : public PDFEngine::Client,
   void DocumentLoadFailed() override;
   void DocumentHasUnsupportedFeature(const std::string& feature) override;
   void DocumentLoadProgress(uint32_t available, uint32_t doc_size) override;
-  void FormTextFieldFocusChange(bool in_focus) override;
+  void FormFieldFocusChange(PDFEngine::FocusFieldType type) override;
   bool IsPrintPreview() const override;
   SkColor GetBackgroundColor() override;
   void SetIsSelecting(bool is_selecting) override;

pdf/pdf_view_web_plugin_unittest.cc

@@ -718,15 +718,31 @@ TEST_F(PdfViewWebPluginTest, FormTextFieldFocusChangeUpdatesTextInputType) {
     EXPECT_CALL(*wrapper_ptr_, UpdateTextInputState);
     EXPECT_CALL(checkpoint, Call);
     EXPECT_CALL(*wrapper_ptr_, UpdateTextInputState);
+    EXPECT_CALL(checkpoint, Call);
+    EXPECT_CALL(*wrapper_ptr_, UpdateTextInputState);
+    EXPECT_CALL(checkpoint, Call);
+    EXPECT_CALL(*wrapper_ptr_, UpdateTextInputState);
   }
 
-  plugin_->FormTextFieldFocusChange(true);
+  plugin_->FormFieldFocusChange(PDFEngine::FocusFieldType::kText);
   EXPECT_EQ(blink::WebTextInputType::kWebTextInputTypeText,
             wrapper_ptr_->widget_text_input_type());
 
   checkpoint.Call();
 
-  plugin_->FormTextFieldFocusChange(false);
+  plugin_->FormFieldFocusChange(PDFEngine::FocusFieldType::kNoFocus);
+  EXPECT_EQ(blink::WebTextInputType::kWebTextInputTypeNone,
+            wrapper_ptr_->widget_text_input_type());
+
+  checkpoint.Call();
+
+  plugin_->FormFieldFocusChange(PDFEngine::FocusFieldType::kText);
+  EXPECT_EQ(blink::WebTextInputType::kWebTextInputTypeText,
+            wrapper_ptr_->widget_text_input_type());
+
+  checkpoint.Call();
+
+  plugin_->FormFieldFocusChange(PDFEngine::FocusFieldType::kNonText);
   EXPECT_EQ(blink::WebTextInputType::kWebTextInputTypeNone,
             wrapper_ptr_->widget_text_input_type());
 }

pdf/pdfium/pdfium_engine.cc

@@ -1040,7 +1040,7 @@ std::vector<uint8_t> PDFiumEngine::PrintPagesAsPdf(
 
 void PDFiumEngine::KillFormFocus() {
   FORM_ForceToKillFocus(form());
-  SetInFormTextArea(false);
+  SetFieldFocus(FocusFieldType::kNoFocus);
 }
 
 void PDFiumEngine::UpdateFocus(bool has_focus) {
@@ -1137,7 +1137,7 @@ void PDFiumEngine::SetFormSelectedText(FPDF_FORMHANDLE form_handle,
   std::string selected_form_text = selected_form_text_;
   selected_form_text_ = base::UTF16ToUTF8(selected_form_text16);
   if (selected_form_text != selected_form_text_) {
-    DCHECK(in_form_text_area_);
+    DCHECK_EQ(focus_field_type_, FocusFieldType::kText);
     client_->SetSelectedText(selected_form_text_);
   }
 }
@@ -1263,10 +1263,10 @@ bool PDFiumEngine::OnLeftMouseDown(const blink::WebMouseEvent& event) {
 
     if (form_type != FPDF_FORMFIELD_UNKNOWN) {
       // FORM_OnLButton*() will trigger a callback to
-      // OnFocusedAnnotationUpdated() which will call SetInFormTextArea().
-      // 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
+      // OnFocusedAnnotationUpdated() which will call SetFieldFocus().
+      // Destroy SelectionChangeInvalidator object before SetFieldFocus()
+      // changes plugin's focus to be `FocusFieldType::kText`. 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).
@@ -1284,7 +1284,7 @@ bool PDFiumEngine::OnLeftMouseDown(const blink::WebMouseEvent& event) {
     if (form_type != FPDF_FORMFIELD_UNKNOWN)
       return true;  // Return now before we get into the selection code.
   }
-  SetInFormTextArea(false);
+  SetFieldFocus(FocusFieldType::kNoFocus);
 
   if (area != PDFiumPage::TEXT_AREA)
     return true;  // Return true so WebKit doesn't do its own highlighting.
@@ -1356,13 +1356,12 @@ bool PDFiumEngine::OnRightMouseDown(const blink::WebMouseEvent& event) {
   }
 
   // Handle the case when focus starts inside a form text area.
-  if (in_form_text_area_) {
+  if (focus_field_type_ == FocusFieldType::kText) {
     if (is_form_text_area) {
       FORM_OnFocus(form(), page, 0, page_x, page_y);
     } else {
       // Transition out of a form text area.
-      FORM_ForceToKillFocus(form());
-      SetInFormTextArea(false);
+      KillFormFocus();
     }
     return true;
   }
@@ -1396,7 +1395,7 @@ bool PDFiumEngine::NavigateToLinkDestination(
     WindowOpenDisposition disposition) {
   if (area == PDFiumPage::WEBLINK_AREA) {
     client_->NavigateTo(target.url, disposition);
-    SetInFormTextArea(false);
+    SetFieldFocus(FocusFieldType::kNoFocus);
     return true;
   }
   if (area == PDFiumPage::DOCLINK_AREA) {
@@ -1417,7 +1416,7 @@ bool PDFiumEngine::NavigateToLinkDestination(
 
       client_->NavigateTo(parameters, disposition);
     }
-    SetInFormTextArea(false);
+    SetFieldFocus(FocusFieldType::kNoFocus);
     return true;
   }
   return false;
@@ -1711,7 +1710,7 @@ bool PDFiumEngine::OnKeyUp(const blink::WebKeyboardEvent& event) {
 
   // Check if form text selection needs to be updated.
   FPDF_PAGE page = pages_[last_focused_page_]->GetPage();
-  if (in_form_text_area_)
+  if (focus_field_type_ == FocusFieldType::kText)
     SetFormSelectedText(form(), page);
 
   return !!FORM_OnKeyUp(form(), page, event.windows_key_code,
@@ -2316,7 +2315,7 @@ void PDFiumEngine::SelectAll() {
   if (IsReadOnly())
     return;
 
-  if (in_form_text_area_) {
+  if (focus_field_type_ == FocusFieldType::kText) {
     if (PageIndexInBounds(last_focused_page_))
       FORM_SelectAllText(form(), pages_[last_focused_page_]->GetPage());
     return;
@@ -3709,7 +3708,7 @@ void PDFiumEngine::GetRegion(const gfx::Point& location,
 }
 
 void PDFiumEngine::OnSelectionTextChanged() {
-  DCHECK(!in_form_text_area_);
+  DCHECK_NE(focus_field_type_, FocusFieldType::kText);
   client_->SetSelectedText(GetSelectedText());
 }
 
@@ -3798,20 +3797,21 @@ void PDFiumEngine::EnteredEditMode() {
   client_->EnteredEditMode();
 }
 
-void PDFiumEngine::SetInFormTextArea(bool in_form_text_area) {
+void PDFiumEngine::SetFieldFocus(PDFEngine::FocusFieldType type) {
   // 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_) {
+  // observer is notified of the change in selection. When `focus_field_type_`
+  // is set to `FocusFieldType::kText`, this is the Renderer. After it flips,
+  // the MimeHandler is notified.
+  if (focus_field_type_ == FocusFieldType::kText) {
     client_->SetSelectedText("");
   }
 
-  client_->FormTextFieldFocusChange(in_form_text_area);
-  in_form_text_area_ = in_form_text_area;
+  client_->FormFieldFocusChange(type);
+  focus_field_type_ = type;
 
   // Clear `editable_form_text_area_` when focus no longer in form text area.
-  if (!in_form_text_area_)
+  if (focus_field_type_ != FocusFieldType::kText)
     editable_form_text_area_ = false;
 }
 
@@ -3940,7 +3940,7 @@ void PDFiumEngine::OnFocusedAnnotationUpdated(FPDF_ANNOTATION annot,
   SetLinkUnderCursorForAnnotation(annot, page_index);
   int form_type = FPDFAnnot_GetFormFieldType(form(), annot);
   if (form_type <= FPDF_FORMFIELD_UNKNOWN) {
-    SetInFormTextArea(false);
+    SetFieldFocus(FocusFieldType::kNoFocus);
     return;
   }
   bool is_form_text_area =
@@ -3949,7 +3949,8 @@ void PDFiumEngine::OnFocusedAnnotationUpdated(FPDF_ANNOTATION annot,
     SelectionChangeInvalidator selection_invalidator(this);
     selection_.clear();
   }
-  SetInFormTextArea(is_form_text_area);
+  SetFieldFocus(is_form_text_area ? FocusFieldType::kText
+                                  : FocusFieldType::kNonText);
   editable_form_text_area_ =
       is_form_text_area && IsAnnotationAnEditableFormTextArea(annot, form_type);
 

pdf/pdfium/pdfium_engine.h

@@ -555,9 +555,8 @@ class PDFiumEngine : public PDFEngine,
   // 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 what type of field has focus.
+  void SetFieldFocus(PDFEngine::FocusFieldType type);
 
   // Sets whether or not left mouse button is currently being held down.
   void SetMouseLeftButtonDown(bool is_mouse_left_button_down);
@@ -715,13 +714,6 @@ class PDFiumEngine : public PDFEngine,
   // Text selection within form text fields and form combobox text fields.
   std::string selected_form_text_;
 
-  // True if focus is in form text field or form combobox text field.
-  bool in_form_text_area_ = false;
-
-  // True if the form text area currently in focus is not read only, and is a
-  // form text field or user-editable form combobox text field.
-  bool editable_form_text_area_ = false;
-
   // True if left mouse button is currently being held down.
   bool mouse_left_button_down_ = false;
 
@@ -760,6 +752,13 @@ class PDFiumEngine : public PDFEngine,
   // Set to true when updating plugin focus.
   bool updating_focus_ = false;
 
+  // True if `focus_field_type_` is currently set to `FocusFieldType::kText` and
+  // the focused form text area is not read-only.
+  bool editable_form_text_area_ = false;
+
+  // The type of the currently focused form field.
+  FocusFieldType focus_field_type_ = FocusFieldType::kNoFocus;
+
   // The focus element type for the currently focused object.
   FocusElementType focus_element_type_ = FocusElementType::kNone;
 

pdf/pdfium/pdfium_engine_unittest.cc

@@ -705,8 +705,8 @@ class PDFiumEngineTabbingTest : public PDFiumTestBase {
     return engine->last_focused_annot_index_;
   }
 
-  bool IsInFormTextArea(PDFiumEngine* engine) {
-    return engine->in_form_text_area_;
+  PDFEngine::FocusFieldType FormFocusFieldType(PDFiumEngine* engine) {
+    return engine->focus_field_type_;
   }
 
   size_t GetSelectionSize(PDFiumEngine* engine) {
@@ -1139,24 +1139,29 @@ TEST_F(PDFiumEngineTabbingTest, VerifyFormFieldStatesOnTabbing) {
   ASSERT_TRUE(engine);
   ASSERT_EQ(1, engine->GetNumberOfPages());
 
+  // Bring focus to the document.
   ASSERT_TRUE(HandleTabEvent(engine.get(), 0));
   EXPECT_EQ(PDFiumEngine::FocusElementType::kDocument,
             GetFocusedElementType(engine.get()));
+  EXPECT_EQ(PDFEngine::FocusFieldType::kNoFocus,
+            FormFocusFieldType(engine.get()));
+  EXPECT_FALSE(engine->CanEditText());
 
-  // Bring focus to the text field.
+  // Bring focus to the text field on the page.
   ASSERT_TRUE(HandleTabEvent(engine.get(), 0));
   EXPECT_EQ(PDFiumEngine::FocusElementType::kPage,
             GetFocusedElementType(engine.get()));
   EXPECT_EQ(0, GetLastFocusedPage(engine.get()));
-  EXPECT_TRUE(IsInFormTextArea(engine.get()));
+  EXPECT_EQ(PDFEngine::FocusFieldType::kText, FormFocusFieldType(engine.get()));
   EXPECT_TRUE(engine->CanEditText());
 
-  // Bring focus to the button.
+  // Bring focus to the button on the page.
   ASSERT_TRUE(HandleTabEvent(engine.get(), 0));
   EXPECT_EQ(PDFiumEngine::FocusElementType::kPage,
             GetFocusedElementType(engine.get()));
   EXPECT_EQ(0, GetLastFocusedPage(engine.get()));
-  EXPECT_FALSE(IsInFormTextArea(engine.get()));
+  EXPECT_EQ(PDFEngine::FocusFieldType::kNonText,
+            FormFocusFieldType(engine.get()));
   EXPECT_FALSE(engine->CanEditText());
 }
 
@@ -1328,7 +1333,10 @@ class ReadOnlyTestClient : public TestClient {
   ReadOnlyTestClient& operator=(const ReadOnlyTestClient&) = delete;
 
   // Mock PDFEngine::Client methods.
-  MOCK_METHOD(void, FormTextFieldFocusChange, (bool), (override));
+  MOCK_METHOD(void,
+              FormFieldFocusChange,
+              (PDFEngine::FocusFieldType),
+              (override));
   MOCK_METHOD(void, SetSelectedText, (const std::string&), (override));
 };
 
@@ -1342,13 +1350,15 @@ TEST_F(PDFiumEngineReadOnlyTest, KillFormFocus) {
 
   // Setting read-only mode should kill form focus.
   EXPECT_FALSE(engine->IsReadOnly());
-  EXPECT_CALL(client, FormTextFieldFocusChange(false));
+  EXPECT_CALL(client,
+              FormFieldFocusChange(PDFEngine::FocusFieldType::kNoFocus));
   engine->SetReadOnly(true);
 
   // Attempting to focus during read-only mode should once more trigger a
   // killing of form focus.
   EXPECT_TRUE(engine->IsReadOnly());
-  EXPECT_CALL(client, FormTextFieldFocusChange(false));
+  EXPECT_CALL(client,
+              FormFieldFocusChange(PDFEngine::FocusFieldType::kNoFocus));
   engine->UpdateFocus(true);
 }
 

pdf/preview_mode_client.cc

@@ -146,7 +146,7 @@ void PreviewModeClient::DocumentHasUnsupportedFeature(
   NOTREACHED();
 }
 
-void PreviewModeClient::FormTextFieldFocusChange(bool in_focus) {
+void PreviewModeClient::FormFieldFocusChange(PDFEngine::FocusFieldType type) {
   NOTREACHED();
 }
 

pdf/preview_mode_client.h

@@ -64,7 +64,7 @@ class PreviewModeClient : public PDFEngine::Client {
   void DocumentLoadComplete() override;
   void DocumentLoadFailed() override;
   void DocumentHasUnsupportedFeature(const std::string& feature) override;
-  void FormTextFieldFocusChange(bool in_focus) override;
+  void FormFieldFocusChange(PDFEngine::FocusFieldType type) override;
   bool IsPrintPreview() const override;
   SkColor GetBackgroundColor() override;
   void SetSelectedText(const std::string& selected_text) override;