Defer saves() until they're needed

src/core/SkPictureRecord.cpp

 /*
  * Copyright 2011 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkPictureRecord.h"
 #include "SkDevice.h"
 #include "SkPatchUtils.h"
@@ skipping 306 matching lines @@
 
 void SkPictureRecord::fillRestoreOffsetPlaceholdersForCurrentStackLevel(uint32_t restoreOffset) {
     int32_t offset = fRestoreOffsetStack.top();
     while (offset > 0) {
         uint32_t peek = fWriter.readTAt<uint32_t>(offset);
         fWriter.overwriteTAt(offset, restoreOffset);
         offset = peek;
     }
 
 #ifdef SK_DEBUG
-    // assert that the final offset value points to a save verb
-    uint32_t opSize;
-    DrawType drawOp = peek_op_and_size(&fWriter, -offset, &opSize);
-    SkASSERT(SAVE == drawOp || SAVE_LAYER == drawOp);
+    // offset of 0 has been disabled, so we skip it
+    if (offset > 0) {
+        // assert that the final offset value points to a save verb
+        uint32_t opSize;
+        DrawType drawOp = peek_op_and_size(&fWriter, -offset, &opSize);
+        SkASSERT(SAVE == drawOp || SAVE_LAYER == drawOp);
+    }
 #endif
 }
 
 void SkPictureRecord::beginRecording() {
     // we have to call this *after* our constructor, to ensure that it gets
     // recorded. This is balanced by restoreToCount() call from endRecording,
     // which in-turn calls our overridden restore(), so those get recorded too.
     fInitialSaveCount = this->save();
 }
 
@@ skipping 699 matching lines @@
 void SkPictureRecord::addTextBlob(const SkTextBlob *blob) {
     int index = fTextBlobRefs.count();
     *fTextBlobRefs.append() = blob;
     blob->ref();
     // follow the convention of recording a 1-based index
     this->addInt(index + 1);
 }
 
 ///////////////////////////////////////////////////////////////////////////////