[PDF] Make stream compression optional on a per device basis.

There are a lot of small pieces to make this change work:
- SkPDFDocument (and SkPDFCatalog) take flags to disable compression (and font embedding - not implemented yet, can disable font subsetting for now).
- SkPDFStream now defers compression until the size/emit step.
- Classes that *had* a stream (because they didn't know the stream size at construction time) now *are* streams to make the substitution work correctly.
- The SkPDFShader implementation got pulled apart into two classes, one that is a SkPDFDict, and one that is a SkPDFStream (making the common ancestor SkPDFObject).
- Added helper methods in SkPDFObject for children that have simple resource lists.
- Added an iterator to SkPDFDict so that a substitute SkPDFStream can get a copy of the stream dictionary.
- Change SkPDFDocument to have a pointer to an SkPDFCatalog to remove a new circular header reference.

Review URL: http://codereview.appspot.com/4700045

git-svn-id: http://skia.googlecode.com/svn/trunk@1911 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/src/pdf/SkPDFDevice.cpp b/src/pdf/SkPDFDevice.cpp
index 7833362..caba822 100644
--- a/src/pdf/SkPDFDevice.cpp
+++ b/src/pdf/SkPDFDevice.cpp
@@ -1394,7 +1394,7 @@
     entry->fClipRegion = clipRegion;
 
     // PDF treats a shader as a color, so we only set one or the other.
-    SkRefPtr<SkPDFShader> pdfShader;
+    SkRefPtr<SkPDFObject> pdfShader;
     const SkShader* shader = paint.getShader();
     SkColor color = paint.getColor();
     if (shader) {