Add PPAPI constructs for sending focus object to PdfAccessibilityTree

This change introduces the PPAPI structures required to send the focus
information from plugin to PdfAccessibilityTree.

Bug: 1015350
Change-Id: I5bfd78b6d34e2ebcf78d9051207fcbc830694678
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2230586Reviewed-by: Daniel Cheng <dcheng@chromium.org>
Reviewed-by: Lei Zhang <thestig@chromium.org>
Reviewed-by: Ankit Kumar 🌪️ <ankk@microsoft.com>
Reviewed-by: Kevin Babbitt <kbabbitt@microsoft.com>
Commit-Queue: Virender Singh <virens@microsoft.com>
Cr-Commit-Position: refs/heads/master@{#793502}

pdf/out_of_process_instance.cc

@@ -813,6 +813,8 @@ void OutOfProcessInstance::SendAccessibilityViewportInfo() {
 
   viewport_info.zoom = zoom_;
   viewport_info.scale = device_scale_;
+  viewport_info.focus_info = {
+      PP_PrivateFocusObjectType::PP_PRIVATEFOCUSOBJECT_NONE, 0, 0};
 
   engine_->GetSelection(&viewport_info.selection_start_page_index,
                         &viewport_info.selection_start_char_index,

ppapi/c/private/ppb_pdf.h

@@ -41,6 +41,32 @@ struct PP_PrivateFindResult {
   int length;
 };
 
+typedef enum {
+  PP_PRIVATEFOCUSOBJECT_NONE = 0,
+  PP_PRIVATEFOCUSOBJECT_DOCUMENT = 1,
+  PP_PRIVATEFOCUSOBJECT_LINK = 2,
+  PP_PRIVATEFOCUSOBJECT_HIGHLIGHT = 3,
+  PP_PRIVATEFOCUSOBJECT_TEXT_FIELD = 4,
+  PP_PRIVATEFOCUSOBJECT_LAST = PP_PRIVATEFOCUSOBJECT_TEXT_FIELD
+} PP_PrivateFocusObjectType;
+
+// Represents the information to uniquely identify the focused object
+// in PDF.
+struct PP_PrivateAccessibilityFocusInfo {
+  // Holds the type of the focused object in PDFiumEngine.
+  PP_PrivateFocusObjectType focused_object_type;
+  // Holds the PDF page index in the which the focused annotation is present.
+  // When |focused_object_type| is PP_PRIVATEFOCUSOBJECT_NONE or
+  // PP_PRIVATEFOCUSOBJECT_DOCUMENT then the value of this member shouldn't
+  // be used, set to zero as a sentinel value.
+  uint32_t focused_object_page_index;
+  // Holds the focused annotation's index in page's annotations array.
+  // When |focused_object_type| is PP_PRIVATEFOCUSOBJECT_NONE or
+  // PP_PRIVATEFOCUSOBJECT_DOCUMENT then the value of this member shouldn't
+  // be used, set to zero as a sentinel value.
+  uint32_t focused_annotation_index_in_page;
+};
+
 struct PP_PrivateAccessibilityViewportInfo {
   double zoom;
   double scale;
@@ -50,6 +76,7 @@ struct PP_PrivateAccessibilityViewportInfo {
   uint32_t selection_start_char_index;
   uint32_t selection_end_page_index;
   uint32_t selection_end_char_index;
+  struct PP_PrivateAccessibilityFocusInfo focus_info;
 };
 
 struct PP_PrivateAccessibilityDocInfo {

ppapi/proxy/ppapi_messages.h

@@ -163,6 +163,7 @@ IPC_ENUM_TRAITS_MAX_VALUE(PP_PrivateChoiceFieldType, PP_PRIVATECHOICEFIELD_LAST)
 IPC_ENUM_TRAITS_MIN_MAX_VALUE(PP_PrivateButtonType,
                               PP_PRIVATEBUTTON_FIRST,
                               PP_PRIVATEBUTTON_LAST)
+IPC_ENUM_TRAITS_MAX_VALUE(PP_PrivateFocusObjectType, PP_PRIVATEFOCUSOBJECT_LAST)
 
 IPC_STRUCT_TRAITS_BEGIN(PP_Point)
   IPC_STRUCT_TRAITS_MEMBER(x)
@@ -269,6 +270,12 @@ IPC_STRUCT_TRAITS_BEGIN(PP_PdfPrintSettings_Dev)
   IPC_STRUCT_TRAITS_MEMBER(scale_factor)
 IPC_STRUCT_TRAITS_END()
 
+IPC_STRUCT_TRAITS_BEGIN(PP_PrivateAccessibilityFocusInfo)
+  IPC_STRUCT_TRAITS_MEMBER(focused_object_type)
+  IPC_STRUCT_TRAITS_MEMBER(focused_object_page_index)
+  IPC_STRUCT_TRAITS_MEMBER(focused_annotation_index_in_page)
+IPC_STRUCT_TRAITS_END()
+
 IPC_STRUCT_TRAITS_BEGIN(PP_PrivateAccessibilityViewportInfo)
   IPC_STRUCT_TRAITS_MEMBER(zoom)
   IPC_STRUCT_TRAITS_MEMBER(scale)
@@ -278,6 +285,7 @@ IPC_STRUCT_TRAITS_BEGIN(PP_PrivateAccessibilityViewportInfo)
   IPC_STRUCT_TRAITS_MEMBER(selection_start_char_index)
   IPC_STRUCT_TRAITS_MEMBER(selection_end_page_index)
   IPC_STRUCT_TRAITS_MEMBER(selection_end_char_index)
+  IPC_STRUCT_TRAITS_MEMBER(focus_info)
 IPC_STRUCT_TRAITS_END()
 
 IPC_STRUCT_TRAITS_BEGIN(PP_PrivateAccessibilityDocInfo)