SkPDF Fix PDF/A to be more valid

src/pdf/SkPDFMetadata.cpp

 /*
  * Copyright 2015 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkMilestone.h"
 #include "SkPDFMetadata.h"
 #include "SkPDFTypes.h"
@@ skipping 245 matching lines @@
             *out++ = input[i];
         }
     }
     if (after) {
         strncpy(out, after, afterLen);
         out += afterLen;
     }
     // Validate that we haven't written outside of our string.
     SkASSERT(out == &output.writable_str()[output.size()]);
     *out = '\0';
-    return std::move(output);
+    return output;
 }
 
 SkPDFObject* SkPDFMetadata::createXMPObject(const UUID& doc,
                                             const UUID& instance) const {
     static const char templateString[] =
             "<?xpacket begin=\"\" id=\"W5M0MpCehiHzreSzNTczkc9d\"?>\n"
             "<x:xmpmeta xmlns:x=\"adobe:ns:meta/\"\n"
             " x:xmptk=\"Adobe XMP Core 5.4-c005 78.147326, "
             "2012/08/23-13:03:03\">\n"
             "<rdf:RDF "
             "xmlns:rdf=\"http://www.w3.org/1999/02/22-rdf-syntax-ns#\">\n"
             "<rdf:Description rdf:about=\"\"\n"
             " xmlns:xmp=\"http://ns.adobe.com/xap/1.0/\"\n"
             " xmlns:dc=\"http://purl.org/dc/elements/1.1/\"\n"
             " xmlns:xmpMM=\"http://ns.adobe.com/xap/1.0/mm/\"\n"
             " xmlns:pdf=\"http://ns.adobe.com/pdf/1.3/\"\n"
             " xmlns:pdfaid=\"http://www.aiim.org/pdfa/ns/id/\">\n"
             "<pdfaid:part>2</pdfaid:part>\n"
             "<pdfaid:conformance>B</pdfaid:conformance>\n"
             "%s"  // ModifyDate
             "%s"  // CreateDate
-            "%s"  // MetadataDate
             "%s"  // xmp:CreatorTool
             "<dc:format>application/pdf</dc:format>\n"
             "%s"  // dc:title
             "%s"  // dc:description
             "%s"  // author
             "%s"  // keywords
             "<xmpMM:DocumentID>uuid:%s</xmpMM:DocumentID>\n"
             "<xmpMM:InstanceID>uuid:%s</xmpMM:InstanceID>\n"
             "<pdf:Producer>Skia/PDF m" SKPDF_STRING(SK_MILESTONE) "</pdf:Producer>\n"
             "%s"  // pdf:Keywords
             "</rdf:Description>\n"
             "</rdf:RDF>\n"
             "</x:xmpmeta>\n"  // Note:  the standard suggests 4k of padding.
             "<?xpacket end=\"w\"?>\n";
 
     SkString creationDate;
     SkString modificationDate;
-    SkString metadataDate;
     if (fCreation) {
         SkString tmp;
         fCreation->toISO8601(&tmp);
         SkASSERT(0 == count_xml_escape_size(tmp));
         // YYYY-mm-ddTHH:MM:SS[+|-]ZZ:ZZ; no need to escape
         creationDate = sk_string_printf("<xmp:CreateDate>%s</xmp:CreateDate>\n",
                                         tmp.c_str());
     }
     if (fModified) {
         SkString tmp;
         fModified->toISO8601(&tmp);
         SkASSERT(0 == count_xml_escape_size(tmp));
         modificationDate = sk_string_printf(
                 "<xmp:ModifyDate>%s</xmp:ModifyDate>\n", tmp.c_str());
-        metadataDate = sk_string_printf(
-                "<xmp:MetadataDate>%s</xmp:MetadataDate>\n", tmp.c_str());
     }
-
-    SkString title =
-            escape_xml(get(fInfo, "Title"), "<dc:title><rdf:Alt><rdf:li>",
-                       "</rdf:li></rdf:Alt></dc:title>\n");
-    SkString author =
-            escape_xml(get(fInfo, "Author"), "<dc:creator><rdf:Bag><rdf:li>",
-                       "</rdf:li></rdf:Bag></dc:creator>\n");
+    SkString title = escape_xml(
+            get(fInfo, "Title"),
+            "<dc:title><rdf:Alt><rdf:li xml:lang=\"x-default\">",
+            "</rdf:li></rdf:Alt></dc:title>\n");
+    SkString author = escape_xml(
+            get(fInfo, "Author"), "<dc:creator><rdf:Bag><rdf:li>",
+            "</rdf:li></rdf:Bag></dc:creator>\n");
     // TODO: in theory, XMP can support multiple authors.  Split on a delimiter?
-    SkString subject = escape_xml(get(fInfo, "Subject"),
-                                  "<dc:description><rdf:Alt><rdf:li>",
-                                  "</rdf:li></rdf:Alt></dc:description>\n");
-    SkString keywords1 =
-            escape_xml(get(fInfo, "Keywords"), "<dc:subject><rdf:Bag><rdf:li>",
-                       "</rdf:li></rdf:Bag></dc:subject>\n");
-    SkString keywords2 = escape_xml(get(fInfo, "Keywords"), "<pdf:Keywords>",
-                                    "</pdf:Keywords>\n");
+    SkString subject = escape_xml(
+            get(fInfo, "Subject"),
+            "<dc:description><rdf:Alt><rdf:li xml:lang=\"x-default\">",
+            "</rdf:li></rdf:Alt></dc:description>\n");
+    SkString keywords1 = escape_xml(
+            get(fInfo, "Keywords"), "<dc:subject><rdf:Bag><rdf:li>",
+            "</rdf:li></rdf:Bag></dc:subject>\n");
+    SkString keywords2 = escape_xml(
+            get(fInfo, "Keywords"), "<pdf:Keywords>",
+            "</pdf:Keywords>\n");
 
     // TODO: in theory, keywords can be a list too.
     SkString creator = escape_xml(get(fInfo, "Creator"), "<xmp:CreatorTool>",
                                   "</xmp:CreatorTool>\n");
     SkString documentID = uuid_to_string(doc);  // no need to escape
     SkASSERT(0 == count_xml_escape_size(documentID));
     SkString instanceID = uuid_to_string(instance);
     SkASSERT(0 == count_xml_escape_size(instanceID));
     return new PDFXMLObject(sk_string_printf(
             templateString, modificationDate.c_str(), creationDate.c_str(),
-            metadataDate.c_str(), creator.c_str(), title.c_str(),
+            creator.c_str(), title.c_str(),
             subject.c_str(), author.c_str(), keywords1.c_str(),
             documentID.c_str(), instanceID.c_str(), keywords2.c_str()));
 }
 
 #endif  // SK_PDF_GENERATE_PDFA
 
 #undef SKPDF_STRING
 #undef SKPDF_STRING_IMPL