formalize named picture versions

BUG=skia:
R=mtklein@google.com, robertphillips@google.com

Author: reed@google.com

Review URL: https://codereview.chromium.org/291913004

git-svn-id: http://skia.googlecode.com/svn/trunk@14807 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/src/core/SkReadBuffer.cpp b/src/core/SkReadBuffer.cpp
index b4bc875..d016d9c 100644
--- a/src/core/SkReadBuffer.cpp
+++ b/src/core/SkReadBuffer.cpp
@@ -25,7 +25,7 @@
 
 SkReadBuffer::SkReadBuffer() {
     fFlags = default_flags();
-    fPictureVersion = 0;
+    fVersion = 0;
     fMemoryPtr = NULL;
 
     fBitmapStorage = NULL;
@@ -43,7 +43,7 @@
 
 SkReadBuffer::SkReadBuffer(const void* data, size_t size) {
     fFlags = default_flags();
-    fPictureVersion = 0;
+    fVersion = 0;
     fReader.setMemory(data, size);
     fMemoryPtr = NULL;
 
@@ -62,7 +62,7 @@
 
 SkReadBuffer::SkReadBuffer(SkStream* stream) {
     fFlags = default_flags();
-    fPictureVersion = 0;
+    fVersion = 0;
     const size_t length = stream->getLength();
     fMemoryPtr = sk_malloc_throw(length);
     stream->read(fMemoryPtr, length);