Add about:flags entry for "pdf-annotations"

Bug: 902646
Change-Id: I1b59c8666c6329b6bb24f4fec31e57b19137e2df
Reviewed-on: https://chromium-review.googlesource.com/c/1373930
Reviewed-by: Lei Zhang <[email protected]>
Reviewed-by: Avi Drissman <[email protected]>
Commit-Queue: dstockwell <[email protected]>
Cr-Commit-Position: refs/heads/master@{#621831}
diff --git a/chrome/browser/about_flags.cc b/chrome/browser/about_flags.cc
index 1595528..79e7168 100644
--- a/chrome/browser/about_flags.cc
+++ b/chrome/browser/about_flags.cc
@@ -3577,6 +3577,12 @@
      FEATURE_VALUE_TYPE(features::kEnableVizHitTestDrawQuad)},
 
 #if BUILDFLAG(ENABLE_PDF)
+#if defined(OS_CHROMEOS)
+    {"pdf-annotations", flag_descriptions::kPdfAnnotations,
+     flag_descriptions::kPdfAnnotationsDescription, kOsCrOS,
+     FEATURE_VALUE_TYPE(chrome_pdf::features::kPDFAnnotations)},
+#endif  // defined(OS_CHROMEOS)
+
     {"pdf-form-save", flag_descriptions::kPdfFormSaveName,
      flag_descriptions::kPdfFormSaveDescription, kOsDesktop,
      FEATURE_VALUE_TYPE(chrome_pdf::features::kSaveEditedPDFForm)},