clean up SkPicture include

Get SkPicture.h ready for documenting.

- remove private methods
- move private forward declarations
- name parameters

R=reed@google.com, bsalomon@google.com

Bug: skia:6898
Change-Id: I28829111203d8ae2a4661cf02c99023403aa0df0
Reviewed-on: https://skia-review.googlesource.com/134120
Reviewed-by: Brian Salomon <bsalomon@google.com>
Reviewed-by: Cary Clark <caryclark@skia.org>
Commit-Queue: Cary Clark <caryclark@google.com>
diff --git a/tools/DumpRecord.cpp b/tools/DumpRecord.cpp
index e9374fd..4c9b1f3 100644
--- a/tools/DumpRecord.cpp
+++ b/tools/DumpRecord.cpp
@@ -7,6 +7,7 @@
 
 #include <stdio.h>
 
+#include "SkPicturePriv.h"
 #include "SkRecord.h"
 #include "SkRecordDraw.h"
 
@@ -63,7 +64,7 @@
     void print(const SkRecords::DrawPicture& command, double ns) {
         this->printNameAndTime(command, ns);
 
-        if (auto bp = command.picture->asSkBigPicture()) {
+        if (auto bp = SkPicturePriv::AsSkBigPicture(command.picture)) {
             ++fIndent;
 
             const SkRecord& record = *bp->record();