Implement NSAccessibilityScrollToVisibleAction on Mac

content/renderer/accessibility/render_accessibility_impl.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 "content/renderer/accessibility/render_accessibility_impl.h"
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include <queue>
@@ skipping 515 matching lines @@
     // Tree-only mode gets used by the automation extension API which requires a
     // load complete event to invoke listener callbacks.
     ui::AXEvent evt = document.accessibilityObject().isLoaded()
         ? ui::AX_EVENT_LOAD_COMPLETE : ui::AX_EVENT_LAYOUT_COMPLETE;
     HandleAXEvent(document.accessibilityObject(), evt);
   }
 }
 
 void RenderAccessibilityImpl::OnScrollToMakeVisible(
     int acc_obj_id, gfx::Rect subfocus) {
+  if (pdf_tree_source_ && pdf_tree_source_->GetFromId(acc_obj_id)) {
+    ScrollPdf(acc_obj_id);
+    return;
+  }
+
   const WebDocument& document = GetMainDocument();
   if (document.isNull())
     return;
 
   WebAXObject obj = document.accessibilityObjectFromID(acc_obj_id);
   if (obj.isDetached()) {
 #ifndef NDEBUG
     LOG(WARNING) << "ScrollToMakeVisible on invalid object id " << acc_obj_id;
 #endif
     return;
@@ skipping 167 matching lines @@
       size_t old_count = update->nodes.size();
       size_t new_count = pdf_update.nodes.size();
       update->nodes.resize(old_count + new_count);
       for (size_t i = 0; i < new_count; ++i)
         update->nodes[old_count + i] = pdf_update.nodes[i];
       break;
     }
   }
 }
 
+void RenderAccessibilityImpl::ScrollPdf(int id_to_make_visible) {
+  // The PDF content doesn't scroll itself, rather it's just one big document
+  // and the embedding page scrolls. So, when we're requested to scroll to make
+  // a particular PDF node visible, get the coordinates of the target PDF node
+  // and then tell the document node to scroll to those coordinates.
+  //
+  // Note that calling scrollToMakeVisibleWithSubFocus() is preferable to
+  // telling the document to scroll to a specific coordinate because it will
+  // first compute whether that rectangle is visible and do nothing if it is.
+  // If it's not visible, it will automatically center it.
+
+  DCHECK(pdf_tree_source_);
+  ui::AXNodeData root_data = pdf_tree_source_->GetRoot()->data();
+  ui::AXNodeData target_data =
+      pdf_tree_source_->GetFromId(id_to_make_visible)->data();
+
+  gfx::RectF bounds = target_data.location;
+  if (root_data.transform)
+    root_data.transform->TransformRect(&bounds);
+
+  const WebDocument& document = GetMainDocument();
+  if (document.isNull())
+    return;
+
+  document.accessibilityObject().scrollToMakeVisibleWithSubFocus(
+      WebRect(bounds.x(), bounds.y(), bounds.width(), bounds.height()));
+}
+
 }  // namespace content