Add contextualization strings to accessibility image labels.

When adding automated descriptions to images in the accessibility
tree, add a contextualization string, "Appears to be:" for a
caption, or "Appears to say:" for OCR, to clearly distinguish
to the user.

Only OCR is completely hooked up, the full label is blocked on
one more change landing first.

(Note: these strings have already been reviewed by Shimi.)

Bug: 905419

Change-Id: Ib39ad7ff8cb43019809dad26f0c9cd32d6f9007a
Reviewed-on: https://chromium-review.googlesource.com/c/1480351
Commit-Queue: Dominic Mazzoni <dmazzoni@chromium.org>
Reviewed-by: John Abd-El-Malek <jam@chromium.org>
Reviewed-by: Ken Rockot <rockot@google.com>
Reviewed-by: Nektarios Paisios <nektar@chromium.org>
Cr-Commit-Position: refs/heads/master@{#634531}

chrome/common/chrome_content_client.cc

@@ -660,6 +660,12 @@ base::string16 ChromeContentClient::GetLocalizedString(int message_id) const {
   return l10n_util::GetStringUTF16(message_id);
 }
 
+base::string16 ChromeContentClient::GetLocalizedString(
+    int message_id,
+    const base::string16& replacement) const {
+  return l10n_util::GetStringFUTF16(message_id, replacement);
+}
+
 base::StringPiece ChromeContentClient::GetDataResource(
     int resource_id,
     ui::ScaleFactor scale_factor) const {

chrome/common/chrome_content_client.h

@@ -84,6 +84,9 @@ class ChromeContentClient : public content::ContentClient {
 
   void AddAdditionalSchemes(Schemes* schemes) override;
   base::string16 GetLocalizedString(int message_id) const override;
+  base::string16 GetLocalizedString(
+      int message_id,
+      const base::string16& replacement) const override;
   base::StringPiece GetDataResource(
       int resource_id,
       ui::ScaleFactor scale_factor) const override;

content/DEPS

@@ -5,6 +5,7 @@ include_rules = [
   # directories in content/ so we disallow all of them.
   "-content",
   "+content/app/resources/grit/content_resources.h",
+  "+content/app/strings/grit",  # For generated headers
   "+content/common",
   "+content/grit",
   "+content/public/common",

content/app/strings/content_strings.grd

@@ -633,6 +633,12 @@ below:
       <message name="IDS_AX_IMAGE_ANNOTATION_PROCESS_FAILED" desc="Accessibility message spoken out loud to screen reader users that the browser was not able to get a description for an image.">
         Unable to get a description.
       </message>
+      <message name="IDS_AX_IMAGE_ANNOTATION_OCR_CONTEXT" desc="Accessibility message spoken out loud to screen reader users when reading text that was automatically extracted from an image, for an example the word 'stop' could be extracted from a photo of a stop sign. Because automatic text extraction sometimes contains errors it is important that the language used indicates some uncertainty - it may say 'stop' or it appears to say 'stop', not it definitely says 'stop'.">
+        Appears to say: <ph name="OCR_TEXT">$1<ex>Stop</ex></ph>
+      </message>
+      <message name="IDS_AX_IMAGE_ANNOTATION_DESCRIPTION_CONTEXT" desc="Accessibility message spoken out loud to screen reader users when reading a computer-generated description of an image, for example a photo of the president at a press conference might be described as 'A person at a podium'. Because automatic image description is sometimes incorrect, it is important that the langauge used indicates some uncertainty - it may be a person, it appears to be a person, not it definitely is a person.">
+        Appears to be: <ph name="DESCRIPTION">$1<ex>A person at a podium</ex></ph>
+      </message>
 
       <message name="IDS_AX_AM_PM_FIELD_TEXT" desc="Accessible description of the AM/PM field in a date/time control">
         AM/PM

content/browser/DEPS

@@ -28,7 +28,6 @@ include_rules = [
   "+components/viz",
   "+components/cbor",
 
-  "+content/app/strings/grit",  # For generated headers
   "+content/public/app",
   "+content/public/browser",
   "+device/base/synchronization",

content/child/DEPS

@@ -6,7 +6,6 @@ include_rules = [
   "+components/webcrypto",
   "+components/services/font/public",
 
-  "+content/app/strings/grit",  # For generated headers
   "+content/public/child",
   "+services/device/public/cpp/device_features.h",
   "+services/device/public/cpp/power_monitor",

content/public/common/content_client.cc

@@ -75,6 +75,12 @@ base::string16 ContentClient::GetLocalizedString(int message_id) const {
   return base::string16();
 }
 
+base::string16 ContentClient::GetLocalizedString(
+    int message_id,
+    const base::string16& replacement) const {
+  return base::string16();
+}
+
 base::StringPiece ContentClient::GetDataResource(
     int resource_id,
     ui::ScaleFactor scale_factor) const {

content/public/common/content_client.h

@@ -156,6 +156,12 @@ class CONTENT_EXPORT ContentClient {
   // Returns a string resource given its id.
   virtual base::string16 GetLocalizedString(int message_id) const;
 
+  // Returns a string resource given its id and replace $1 with the given
+  // replacement.
+  virtual base::string16 GetLocalizedString(
+      int message_id,
+      const base::string16& replacement) const;
+
   // Return the contents of a resource in a StringPiece given the resource id.
   virtual base::StringPiece GetDataResource(
       int resource_id,

content/renderer/BUILD.gn

@@ -612,6 +612,7 @@ target(link_target_type, "renderer") {
     "//components/viz/common",
     "//components/viz/service",
     "//content:resources",
+    "//content/app/strings:strings_grit",
     "//content/child",
     "//content/common",
     "//content/common:buildflags",

content/renderer/accessibility/ax_image_annotator.cc

@@ -6,6 +6,10 @@
 
 #include "base/base64.h"
 #include "base/stl_util.h"
+#include "base/strings/string_number_conversions.h"
+#include "base/strings/utf_string_conversions.h"
+#include "content/app/strings/grit/content_strings.h"
+#include "content/public/common/content_client.h"
 #include "content/renderer/render_frame_impl.h"
 #include "crypto/sha2.h"
 #include "third_party/blink/public/web/web_ax_object.h"
@@ -177,9 +181,16 @@ void AXImageAnnotator::OnImageAnnotated(
     DLOG(WARNING) << "Unrecognized image annotation result.";
     return;
   }
-  // TODO(nektar): Add message to explain that the annotation is a best guess,
-  // e.g. "appears to be".
-  image_annotations_.at(image.AxID()).set_annotation(result->get_ocr_text());
+
+  if (result->get_ocr_text().empty())
+    return;
+
+  auto contextualized_string = GetContentClient()->GetLocalizedString(
+      IDS_AX_IMAGE_ANNOTATION_OCR_CONTEXT,
+      base::UTF8ToUTF16(result->get_ocr_text()));
+
+  image_annotations_.at(image.AxID())
+      .set_annotation(base::UTF16ToUTF8(contextualized_string));
   render_accessibility_->MarkWebAXObjectDirty(image, false /* subtree */);
 }
 

content/renderer/accessibility/blink_ax_tree_source.cc

@@ -886,8 +886,15 @@ void BlinkAXTreeSource::SerializeNode(WebAXObject src,
     if (image_annotator_->HasAnnotationInCache(src)) {
       dst->AddStringAttribute(ax::mojom::StringAttribute::kImageAnnotation,
                               image_annotator_->GetImageAnnotation(src));
+      dst->SetImageAnnotationStatus(
+          ax::mojom::ImageAnnotationStatus::kAnnotationSucceeded);
+    } else if (image_annotator_->HasImageInCache(src)) {
+      dst->SetImageAnnotationStatus(
+          ax::mojom::ImageAnnotationStatus::kAnnotationPending);
     } else if (!image_annotator_->HasImageInCache(src)) {
       image_annotator_->OnImageAdded(src);
+      dst->SetImageAnnotationStatus(
+          ax::mojom::ImageAnnotationStatus::kAnnotationPending);
     }
   }
 

content/shell/DEPS

@@ -9,7 +9,6 @@ include_rules = [
 
   # The content_shell is the canonical sample embedder, so it only uses
   # content's public API.
-  "+content/app/strings/grit",  # For generated headers
   "+content/public",
 
   "+services/network/ignore_errors_cert_verifier.h",