document.close from bool to void

Nothing meaningful is returned, it is inconsistent with the bulk of the rest of skia's api. The C api is waiting on this change as well.

Required chrome CL: https://codereview.chromium.org/2355343003/

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2354403002

Review-Url: https://codereview.chromium.org/2354403002
diff --git a/src/pdf/SkPDFDocument.cpp b/src/pdf/SkPDFDocument.cpp
index 8734927..ab5f465 100644
--- a/src/pdf/SkPDFDocument.cpp
+++ b/src/pdf/SkPDFDocument.cpp
@@ -399,11 +399,11 @@
     return intentArray;
 }
 
-bool SkPDFDocument::onClose(SkWStream* stream) {
+void SkPDFDocument::onClose(SkWStream* stream) {
     SkASSERT(!fCanvas.get());
     if (fPages.empty()) {
         this->reset();
-        return false;
+        return;
     }
     auto docCatalog = sk_make_sp<SkPDFDict>("Catalog");
     if (fPDFA) {
@@ -428,7 +428,6 @@
     fObjectSerializer.serializeObjects(this->getStream());
     fObjectSerializer.serializeFooter(this->getStream(), docCatalog, fID);
     this->reset();
-    return true;
 }
 
 ///////////////////////////////////////////////////////////////////////////////