Add new experimental API to SkPicture to get "id" of current op

src/core/SkPicturePlayback.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 <new>
 #include "SkBBoxHierarchy.h"
 #include "SkOffsetTable.h"
 #include "SkPicturePlayback.h"
@@ skipping 243 matching lines @@
 void SkPicturePlayback::init() {
     fBitmaps = NULL;
     fPaints = NULL;
     fPictureRefs = NULL;
     fPictureCount = 0;
     fOpData = NULL;
     fFactoryPlayback = NULL;
     fBoundingHierarchy = NULL;
     fStateTree = NULL;
     fCachedActiveOps = NULL;
+    fCurOffset = 0;
 }
 
 SkPicturePlayback::~SkPicturePlayback() {
     SkSafeUnref(fOpData);
 
     SkSafeUnref(fBitmaps);
     SkSafeUnref(fPaints);
     SkSafeUnref(fBoundingHierarchy);
     SkSafeUnref(fStateTree);
 
@@ skipping 557 matching lines @@
     if (0 != fCachedActiveOps->fOps.count()) {
         SkTQSort<SkPictureStateTree::Draw>(
             reinterpret_cast<SkPictureStateTree::Draw**>(fCachedActiveOps->fOps.begin()),
             reinterpret_cast<SkPictureStateTree::Draw**>(fCachedActiveOps->fOps.end()-1));
     }
 
     fCachedActiveOps->fCacheQueryRect = query;
     return *fCachedActiveOps;
 }
 
+class SkAutoResetOpID {
+public:
+    SkAutoResetOpID(SkPicturePlayback* playback) : fPlayback(playback) { }
+    ~SkAutoResetOpID() {
+        if (NULL != fPlayback) {
+            fPlayback->resetOpID();
+        }
+    }
+
+private:
+    SkPicturePlayback* fPlayback;
+};
+
 void SkPicturePlayback::draw(SkCanvas& canvas, SkDrawPictureCallback* callback) {
+    SkAutoResetOpID aroi(this);
+    SkASSERT(0 == fCurOffset);
+
 #ifdef ENABLE_TIME_DRAW
     SkAutoTime  at("SkPicture::draw", 50);
 #endif
 
 #ifdef SPEW_CLIP_SKIPPING
     SkipClipRec skipRect, skipRRect, skipRegion, skipPath, skipCull;
     int opCount = 0;
 #endif
 
 #ifdef SK_BUILD_FOR_ANDROID
@@ skipping 60 matching lines @@
 #ifdef SK_BUILD_FOR_ANDROID
         if (fAbortCurrentPlayback) {
             return;
         }
 #endif
 
 #ifdef SPEW_CLIP_SKIPPING
         opCount++;
 #endif
 
-        size_t curOffset = reader.offset();
+        fCurOffset = reader.offset();
         uint32_t size;
         DrawType op = read_op_and_size(&reader, &size);
         size_t skipTo = 0;
         if (NOOP == op) {
             // NOOPs are to be ignored - do not propagate them any further
-            skipTo = curOffset + size;
+            skipTo = fCurOffset + size;
 #ifdef SK_DEVELOPER
         } else {
             opIndex++;
             if (this->preDraw(opIndex, op)) {
-                skipTo = curOffset + size;
+                skipTo = fCurOffset + size;
             }
 #endif
         }
 
         if (0 != skipTo) {
             if (it.isValid()) {
                 // If using a bounding box hierarchy, advance the state tree
                 // iterator until at or after skipTo
                 uint32_t adjustedSkipTo;
                 do {
@@ skipping 861 matching lines @@
     for (index = 0; index < fPictureCount; index++)
         bufferPtr += snprintf(bufferPtr, DUMP_BUFFER_SIZE - (bufferPtr - pBuffer),
             "picture%p, ", fPictureRefs[index]);
     if (fPictureCount > 0)
         SkDebugf("%s0};\n", pBuffer);
 
     const_cast<SkPicturePlayback*>(this)->dumpStream();
 }
 
 #endif