Revert "Reload the PDF accessibility tree on layout changes"

This reverts commit 2d0cae27.

Reason for revert: The CL caused test failures on PDFExtensionTestWithParam.PdfAccessibilityTextRunCrash
Example failure:
https://ci.chromium.org/p/chrome/builders/ci/linux-chromeos-chrome/10202
The test is only enabled with gn arg is_chrome_branded = true which explains why it got missed in CQ.
(when reproing locally, I also ran into crbug.com/1152752 , so if you want to repro make sure to turn dchecks off :-D )

Original change's description:
> Reload the PDF accessibility tree on layout changes
>
> Currently, any layout changes applied to the PDF document (i.e. page
> rotation or two-up view) after the accessibility tree has loaded does
> not update the page bounds.
>
> Because the accessiblity tree has read-only nodes, the only way to
> resolve the issue is to reload all the nodes of the tree on each layout
> change.
>
> Note: This CL only fixes page bounds and positions. The bounds of page
> content such as text or annotations still do not rotate with the rest
> of the document. Those issues will be fixed in a follow-up.
>
> Bug: 1150665
> Change-Id: I2fbf2cb26f38ee3fed076333c0b224a8ede7947e
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2553217
> Commit-Queue: Daniel Hosseinian <dhoss@chromium.org>
> Reviewed-by: Ankit Kumar 🌪️ <ankk@microsoft.com>
> Reviewed-by: Raymes Khoury <raymes@chromium.org>
> Reviewed-by: Dominic Mazzoni <dmazzoni@chromium.org>
> Reviewed-by: Tom Sepez <tsepez@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#830918}

TBR=raymes@chromium.org,dmazzoni@chromium.org,tsepez@chromium.org,dhoss@chromium.org,ankk@microsoft.com

Change-Id: I6c2946592cfcb496c6ed2cd3de6610e2d7c64902
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: 1150665
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2560263Reviewed-by: Pavol Marko <pmarko@chromium.org>
Commit-Queue: Pavol Marko <pmarko@chromium.org>
Cr-Commit-Position: refs/heads/master@{#830971}

components/pdf/renderer/pdf_accessibility_tree.cc

@@ -1302,7 +1302,6 @@ void PdfAccessibilityTree::SetAccessibilityDocInfo(
   if (!render_accessibility)
     return;
 
-  ClearAccessibilityNodes();
   doc_info_ = doc_info;
   doc_node_ =
       CreateNode(ax::mojom::Role::kDocument, ax::mojom::Restriction::kReadOnly,
@@ -1324,11 +1323,6 @@ void PdfAccessibilityTree::SetAccessibilityPageInfo(
     const std::vector<ppapi::PdfAccessibilityTextRunInfo>& text_runs,
     const std::vector<PP_PrivateAccessibilityCharInfo>& chars,
     const ppapi::PdfAccessibilityPageObjects& page_objects) {
-  // Outdated calls are ignored.
-  uint32_t page_index = page_info.page_index;
-  if (page_index != next_page_index_)
-    return;
-
   content::RenderAccessibility* render_accessibility = GetRenderAccessibility();
   if (!render_accessibility)
     return;
@@ -1342,9 +1336,9 @@ void PdfAccessibilityTree::SetAccessibilityPageInfo(
   if (invalid_plugin_message_received_)
     return;
 
+  uint32_t page_index = page_info.page_index;
   CHECK_GE(page_index, 0U);
   CHECK_LT(page_index, doc_info_.page_count);
-  ++next_page_index_;
 
   ui::AXNodeData* page_node =
       CreateNode(ax::mojom::Role::kRegion, ax::mojom::Restriction::kReadOnly,
@@ -1466,13 +1460,6 @@ bool PdfAccessibilityTree::FindCharacterOffset(
   return true;
 }
 
-void PdfAccessibilityTree::ClearAccessibilityNodes() {
-  next_page_index_ = 0;
-  nodes_.clear();
-  node_id_to_page_char_index_.clear();
-  node_id_to_annotation_info_.clear();
-}
-
 content::RenderAccessibility* PdfAccessibilityTree::GetRenderAccessibility() {
   content::RenderFrame* render_frame =
       host_->GetRenderFrameForInstance(instance_);

components/pdf/renderer/pdf_accessibility_tree.h

@@ -121,10 +121,6 @@ class PdfAccessibilityTree : public content::PluginAXTreeSource {
       const ppapi::PdfAccessibilityPageObjects& page_objects,
       content::RenderAccessibility* render_accessibility);
 
-  // Clears the local cache of node data used to create the tree so that
-  // replacement node data can be introduced.
-  void ClearAccessibilityNodes();
-
   content::RenderAccessibility* GetRenderAccessibility();
   std::unique_ptr<gfx::Transform> MakeTransformFromViewInfo() const;
 
@@ -167,10 +163,6 @@ class PdfAccessibilityTree : public content::PluginAXTreeSource {
   // object to which an action can be passed.
   std::map<int32_t, AnnotationInfo> node_id_to_annotation_info_;
   bool invalid_plugin_message_received_ = false;
-
-  // Index of the next expected PDF accessibility page info, used to ignore
-  // outdated calls of SetAccessibilityPageInfo().
-  uint32_t next_page_index_ = 0;
 };
 
 }  // namespace pdf

components/pdf/renderer/pdf_accessibility_tree_browsertest.cc

@@ -233,45 +233,6 @@ TEST_F(PdfAccessibilityTreeTest, TestAccessibilityDisabledDuringPDFLoad) {
                                                   chars_, page_objects_);
 }
 
-TEST_F(PdfAccessibilityTreeTest, TestPdfAccessibilityTreeReload) {
-  content::RenderFrame* render_frame = view_->GetMainRenderFrame();
-  ASSERT_TRUE(render_frame);
-  render_frame->SetAccessibilityModeForTest(ui::AXMode::kWebContents);
-  ASSERT_TRUE(render_frame->GetRenderAccessibility());
-
-  FakeRendererPpapiHost host(view_->GetMainRenderFrame());
-  PP_Instance instance = 0;
-  pdf::PdfAccessibilityTree pdf_accessibility_tree(&host, instance);
-
-  // Make the accessibility tree with a portrait page and then remake with a
-  // landscape page.
-  gfx::RectF page_bounds = gfx::RectF(1, 2);
-  for (size_t i = 1; i <= 2; ++i) {
-    if (i == 2)
-      page_bounds.Transpose();
-
-    page_info_.bounds =
-        PP_MakeRectFromXYWH(page_bounds.x(), page_bounds.y(),
-                            page_bounds.width(), page_bounds.height());
-    pdf_accessibility_tree.SetAccessibilityViewportInfo(viewport_info_);
-    pdf_accessibility_tree.SetAccessibilityDocInfo(doc_info_);
-    pdf_accessibility_tree.SetAccessibilityPageInfo(page_info_, text_runs_,
-                                                    chars_, page_objects_);
-
-    ui::AXNode* root_node = pdf_accessibility_tree.GetRoot();
-    ASSERT_TRUE(root_node);
-    EXPECT_EQ(ax::mojom::Role::kDocument, root_node->data().role);
-
-    // There should only be one page node.
-    ASSERT_EQ(1u, root_node->children().size());
-
-    ui::AXNode* page_node = root_node->children()[0];
-    ASSERT_TRUE(page_node);
-    EXPECT_EQ(ax::mojom::Role::kRegion, page_node->data().role);
-    EXPECT_EQ(page_bounds, page_node->data().relative_bounds.bounds);
-  }
-}
-
 TEST_F(PdfAccessibilityTreeTest, TestPdfAccessibilityTreeCreation) {
   static const char kTestAltText[] = "Alternate text for image";
 

pdf/out_of_process_instance.cc

@@ -816,10 +816,6 @@ void OutOfProcessInstance::LoadAccessibility() {
   doc_info.text_copyable =
       PP_FromBool(engine()->HasPermission(PDFEngine::PERMISSION_COPY));
 
-  // A new document layout will trigger the creation of a new accessibility
-  // tree, so |next_accessibility_page_index_| should be reset to ignore
-  // outdated asynchronous calls of SendNextAccessibilityPage().
-  next_accessibility_page_index_ = 0;
   pp::PDF::SetAccessibilityDocInfo(GetPluginInstance(), &doc_info);
 
   // If the document contents isn't accessible, don't send anything more.
@@ -840,11 +836,6 @@ void OutOfProcessInstance::LoadAccessibility() {
 }
 
 void OutOfProcessInstance::SendNextAccessibilityPage(int32_t page_index) {
-  // Outdated calls are ignored.
-  if (page_index != next_accessibility_page_index_)
-    return;
-  ++next_accessibility_page_index_;
-
   AccessibilityPageInfo page_info;
   std::vector<pp::PDF::PrivateAccessibilityTextRunInfo> text_runs;
   std::vector<AccessibilityCharInfo> chars;
@@ -1245,11 +1236,6 @@ void OutOfProcessInstance::ProposeDocumentLayout(const DocumentLayout& layout) {
   }
   dimensions.Set(kJSPageDimensions, page_dimensions_array);
   PostMessage(dimensions);
-
-  // Reload the accessibility tree on layout changes because the relative page
-  // bounds are no longer valid.
-  if (layout.dirty() && accessibility_state_ == ACCESSIBILITY_STATE_LOADED)
-    LoadAccessibility();
 }
 
 void OutOfProcessInstance::Invalidate(const gfx::Rect& rect) {

pdf/out_of_process_instance.h

@@ -523,10 +523,6 @@ class OutOfProcessInstance : public PdfViewPluginBase,
     ACCESSIBILITY_STATE_LOADED
   } accessibility_state_ = ACCESSIBILITY_STATE_OFF;
 
-  // The next accessibility page index, used to track interprocess calls when
-  // reconstructing the tree for new document layouts.
-  int32_t next_accessibility_page_index_ = 0;
-
   base::WeakPtrFactory<OutOfProcessInstance> weak_factory_{this};
 };