Revert "Add viewport scroll information to PDFAccessibilityTree"

This reverts commit c2f0727826.

Reason for revert: This change is causing regression. Bounding box
calculation of a given element requires the |kScrollX| and |kScrollY|
positions. In case of PDF there is a scroll element which lives outside
the PDF node. The scroll element also reports scroll positions. During
calculation of bounding boxes in AXTree::RelativeToTreeBoundsInternal
|kScrollX| and |kScrollY| are applied twice.

Original change's description:
> Add viewport scroll information to PDFAccessibilityTree
>
> This CL adds following information to PDFAccessibilityTree
> - ax::mojom::IntAttribute::kScrollXMin
> - ax::mojom::IntAttribute::kScrollXMax
> - ax::mojom::IntAttribute::kScrollX
> - ax::mojom::IntAttribute::kScrollYMin
> - ax::mojom::IntAttribute::kScrollYMax
> - ax::mojom::IntAttribute::kScrollY
>
> It enables partial implementation of IScrollProvider, following methods
> will work with this change
> - IScrollProvider::get_HorizontallyScrollable
> - IScrollProvider::get_VerticallyScrollable
> - IScrollProvider::get_HorizontalScrollPercent
> - IScrollProvider::get_VerticalScrollPercent
>
> This information is required by Screen readers to announce the current
> scroll position and extent of scroll to the user.
>
> Tests: The best way to test this change will be through browser tests.
> However, it requires the second part of the change, detailed in the
> associated bug, to be completed.
>
> Bug: 1034521
> Change-Id: I629b2773c75f2b6b222d339cd0ae01799d695295
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1985821
> Reviewed-by: Daniel Cheng <dcheng@chromium.org>
> Reviewed-by: Lei Zhang <thestig@chromium.org>
> Commit-Queue: Virender Singh <virens@microsoft.com>
> Cr-Commit-Position: refs/heads/master@{#728843}

TBR=dcheng@chromium.org,thestig@chromium.org,mohitb@microsoft.com,virens@microsoft.com

# Not skipping CQ checks because original CL landed > 1 day ago.

Bug: 1034521
Change-Id: I15675f9ba604be96e9c50c9bea1dbe84ef8c9a0a
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2041714
Reviewed-by: Lei Zhang <thestig@chromium.org>
Commit-Queue: Lei Zhang <thestig@chromium.org>
Cr-Commit-Position: refs/heads/master@{#739108}

components/pdf/renderer/pdf_accessibility_tree.cc

@@ -362,16 +362,6 @@ void PdfAccessibilityTree::SetAccessibilityViewportInfo(
   if (render_accessibility && tree_.size() > 1) {
     ui::AXNode* root = tree_.root();
     ui::AXNodeData root_data = root->data();
-    root_data.AddIntAttribute(ax::mojom::IntAttribute::kScrollXMin, 0);
-    root_data.AddIntAttribute(ax::mojom::IntAttribute::kScrollXMax,
-                              viewport_info.total_scrollable_size.width);
-    root_data.AddIntAttribute(ax::mojom::IntAttribute::kScrollX,
-                              viewport_info.current_scroll_position.x);
-    root_data.AddIntAttribute(ax::mojom::IntAttribute::kScrollYMin, 0);
-    root_data.AddIntAttribute(ax::mojom::IntAttribute::kScrollYMax,
-                              viewport_info.total_scrollable_size.height);
-    root_data.AddIntAttribute(ax::mojom::IntAttribute::kScrollY,
-                              viewport_info.current_scroll_position.y);
     root_data.relative_bounds.transform =
         base::WrapUnique(MakeTransformFromViewInfo());
     root->SetData(root_data);

components/pdf/renderer/pdf_accessibility_tree_browsertest.cc

@@ -173,8 +173,6 @@ class PdfAccessibilityTreeTest : public content::RenderViewTest {
 
     viewport_info_.zoom = 1.0;
     viewport_info_.scale = 1.0;
-    viewport_info_.total_scrollable_size = {0, 0};
-    viewport_info_.current_scroll_position = {0, 0};
     viewport_info_.scroll = {0, 0};
     viewport_info_.offset = {0, 0};
     viewport_info_.selection_start_page_index = 0;

pdf/out_of_process_instance.cc

@@ -1017,10 +1017,6 @@ void OutOfProcessInstance::SendAccessibilityViewportInfo() {
 
   viewport_info.zoom = zoom_;
   viewport_info.scale = device_scale_;
-  viewport_info.total_scrollable_size = {GetTotalScrollableWidth(),
-                                         GetTotalScrollableHeight()};
-  viewport_info.current_scroll_position = {GetHorizontalScrollPosition(),
-                                           GetVerticalScrollPosition()};
 
   engine_->GetSelection(&viewport_info.selection_start_page_index,
                         &viewport_info.selection_start_char_index,
@@ -1303,25 +1299,6 @@ int OutOfProcessInstance::GetDocumentPixelHeight() const {
       ceil(document_size_.height() * zoom_ * device_scale_));
 }
 
-int OutOfProcessInstance::GetTotalScrollableWidth() const {
-  return std::max(GetDocumentPixelWidth() - plugin_size_.width(), 0);
-}
-
-int OutOfProcessInstance::GetTotalScrollableHeight() const {
-  return std::max(static_cast<int>(GetDocumentPixelHeight() +
-                                   GetToolbarHeightInScreenCoords() -
-                                   plugin_size_.height()),
-                  0);
-}
-
-int OutOfProcessInstance::GetHorizontalScrollPosition() const {
-  return static_cast<int>(scroll_offset_.x() * device_scale_);
-}
-
-int OutOfProcessInstance::GetVerticalScrollPosition() const {
-  return static_cast<int>(scroll_offset_.y() * device_scale_);
-}
-
 void OutOfProcessInstance::FillRect(const pp::Rect& rect, uint32_t color) {
   DCHECK(!image_data_.is_null() || rect.IsEmpty());
   uint32_t* buffer_start = static_cast<uint32_t*>(image_data_.data());
@@ -2017,7 +1994,7 @@ void OutOfProcessInstance::IsEditModeChanged(bool is_edit_mode) {
   pp::PDF::SetPluginCanSave(this, ShouldSaveEdits());
 }
 
-float OutOfProcessInstance::GetToolbarHeightInScreenCoords() const {
+float OutOfProcessInstance::GetToolbarHeightInScreenCoords() {
   return top_toolbar_height_in_viewport_coords_ * device_scale_;
 }
 

pdf/out_of_process_instance.h

@@ -149,7 +149,7 @@ class OutOfProcessInstance : public pp::Instance,
   void IsSelectingChanged(bool is_selecting) override;
   void SelectionChanged(const pp::Rect& left, const pp::Rect& right) override;
   void IsEditModeChanged(bool is_edit_mode) override;
-  float GetToolbarHeightInScreenCoords() const override;
+  float GetToolbarHeightInScreenCoords() override;
 
   // PreviewModeClient::Client implementation.
   void PreviewDocumentLoadComplete() override;
@@ -180,14 +180,6 @@ class OutOfProcessInstance : public pp::Instance,
   int GetDocumentPixelWidth() const;
   int GetDocumentPixelHeight() const;
 
-  // Computes total scrollable Width and Height of the document.
-  int GetTotalScrollableWidth() const;
-  int GetTotalScrollableHeight() const;
-
-  // Computes current horizontal and scroll position of the document.
-  int GetHorizontalScrollPosition() const;
-  int GetVerticalScrollPosition() const;
-
   // Draws a rectangle with the specified dimensions and color in our buffer.
   void FillRect(const pp::Rect& rect, uint32_t color);
 

pdf/pdf_engine.h

@@ -282,7 +282,7 @@ class PDFEngine {
 
     // Gets the height of the top toolbar in screen coordinates. This is
     // independent of whether it is hidden or not at the moment.
-    virtual float GetToolbarHeightInScreenCoords() const = 0;
+    virtual float GetToolbarHeightInScreenCoords() = 0;
   };
 
   struct AccessibilityLinkInfo {

pdf/preview_mode_client.cc

@@ -150,7 +150,7 @@ bool PreviewModeClient::IsPrintPreview() {
   return false;
 }
 
-float PreviewModeClient::GetToolbarHeightInScreenCoords() const {
+float PreviewModeClient::GetToolbarHeightInScreenCoords() {
   return 0.0f;
 }
 

pdf/preview_mode_client.h

@@ -67,7 +67,7 @@ class PreviewModeClient : public PDFEngine::Client {
   void DocumentHasUnsupportedFeature(const std::string& feature) override;
   void FormTextFieldFocusChange(bool in_focus) override;
   bool IsPrintPreview() override;
-  float GetToolbarHeightInScreenCoords() const override;
+  float GetToolbarHeightInScreenCoords() override;
   uint32_t GetBackgroundColor() override;
 
  private:

pdf/test/test_client.cc

@@ -56,7 +56,7 @@ uint32_t TestClient::GetBackgroundColor() {
   return 0;
 }
 
-float TestClient::GetToolbarHeightInScreenCoords() const {
+float TestClient::GetToolbarHeightInScreenCoords() {
   return 0;
 }
 

pdf/test/test_client.h

@@ -37,7 +37,7 @@ class TestClient : public PDFEngine::Client {
   pp::Instance* GetPluginInstance() override;
   bool IsPrintPreview() override;
   uint32_t GetBackgroundColor() override;
-  float GetToolbarHeightInScreenCoords() const override;
+  float GetToolbarHeightInScreenCoords() override;
 
  private:
   // Not owned. Expected to dangle briefly, as the engine usually is destroyed

ppapi/c/private/ppb_pdf.h

@@ -36,10 +36,6 @@ struct PP_PrivateFindResult {
 struct PP_PrivateAccessibilityViewportInfo {
   double zoom;
   double scale;
-  // |total_scrollable_size| and |current_scroll_position| are relative
-  // to plugin embed and in screen coordinates.
-  struct PP_Size total_scrollable_size;
-  struct PP_Point current_scroll_position;
   struct PP_Point scroll;
   struct PP_Point offset;
   uint32_t selection_start_page_index;

ppapi/proxy/ppapi_messages.h

@@ -268,8 +268,6 @@ IPC_STRUCT_TRAITS_END()
 IPC_STRUCT_TRAITS_BEGIN(PP_PrivateAccessibilityViewportInfo)
   IPC_STRUCT_TRAITS_MEMBER(zoom)
   IPC_STRUCT_TRAITS_MEMBER(scale)
-  IPC_STRUCT_TRAITS_MEMBER(total_scrollable_size)
-  IPC_STRUCT_TRAITS_MEMBER(current_scroll_position)
   IPC_STRUCT_TRAITS_MEMBER(scroll)
   IPC_STRUCT_TRAITS_MEMBER(offset)
   IPC_STRUCT_TRAITS_MEMBER(selection_start_page_index)