Add SkPDFResourceDict class, refactor existing code

src/pdf/SkPDFFormXObject.cpp

Index: src/pdf/SkPDFFormXObject.cpp
diff --git a/src/pdf/SkPDFFormXObject.cpp b/src/pdf/SkPDFFormXObject.cpp
index 884e6db2e4a1535c20d6f1dd62e87e637eceb2c1..1b1287123cb0295d76f1239a4df982c4d713e5c9 100644
--- a/src/pdf/SkPDFFormXObject.cpp
+++ b/src/pdf/SkPDFFormXObject.cpp
@@ -12,6 +12,7 @@
 #include "SkMatrix.h"
 #include "SkPDFCatalog.h"
 #include "SkPDFDevice.h"
+#include "SkPDFResourceDict.h"
 #include "SkPDFUtils.h"
 #include "SkStream.h"
 #include "SkTypes.h"
@@ -21,7 +22,8 @@ SkPDFFormXObject::SkPDFFormXObject(SkPDFDevice* device) {
     // of content, so reference or copy everything we need (content and
     // resources).
     SkTSet<SkPDFObject*> emptySet;
-    device->getResources(emptySet, &fResources, false);
+    SkPDFResourceDict* resourceDict = device->getResourceDict();
+    resourceDict->getRefResources(emptySet, &fResources, false);
 
     SkAutoTUnref<SkStream> content(device->content());
     setData(content.get());
@@ -29,7 +31,7 @@ SkPDFFormXObject::SkPDFFormXObject(SkPDFDevice* device) {
     insertName("Type", "XObject");
     insertName("Subtype", "Form");
     SkSafeUnref(this->insert("BBox", device->copyMediaBox()));
-    insert("Resources", device->getResourceDict());
+    insert("Resources", resourceDict);
 
     // We invert the initial transform and apply that to the xobject so that
     // it doesn't get applied twice. We can't just undo it because it's