SkPDF: add basic metadata support

tests/PDFMetadataAttributeTest.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 "SkDocument.h"
+#include "SkStream.h"
+#include "SkData.h"
+#include "Test.h"
+
+DEF_TEST(SkPDF_MetadataAttribute, r) {
+    REQUIRE_PDF_DOCUMENT(SkPDF_MetadataAttribute, r);
+    SkDynamicMemoryWStream pdf;
+    SkAutoTUnref<SkDocument> doc(SkDocument::CreatePDF(&pdf));
+    SkTArray<SkDocument::Attribute> info;
+    info.emplace_back(SkString("Title"), SkString("A1"));
+    info.emplace_back(SkString("Author"), SkString("A2"));
+    info.emplace_back(SkString("Subject"), SkString("A3"));
+    info.emplace_back(SkString("Keywords"), SkString("A4"));
+    info.emplace_back(SkString("Creator"), SkString("A5"));
+    SkTime::DateTime now;
+    SkTime::GetDateTime(&now);
+    doc->setMetadata(info, &now, &now);
+    doc->beginPage(612.0f, 792.0f);
+    doc->close();
+    SkAutoTUnref<SkData> data(pdf.copyToData());
+    static const char* expectations[] = {
+        "/Title (A1)",
+        "/Author (A2)",
+        "/Subject (A3)",
+        "/Keywords (A4)",
+        "/Creator (A5)",
+        "/Producer (Skia/PDF)",
+        "/CreationDate (D:",
+        "/ModDate (D:"
+    };
+    for (const char* expectation : expectations) {
+        bool found = false;
+        size_t N = 1 + data->size() - strlen(expectation);
+        for (size_t i = 0; i < N; ++i) {
+            if (0 == memcmp(data->bytes() + i,
+                             expectation, strlen(expectation))) {
+                found = true;
+                break;
+            }
+        }
+        if (!found) {
+            ERRORF(r, "expectation missing: '%s'.", expectation);
+        }
+    }
+}