Enforce thread-safety of bitmaps in pictures via the type.

src/core/SkRecordDraw.cpp

 /*
  * Copyright 2014 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkLayerInfo.h"
 #include "SkRecordDraw.h"
 #include "SkPatchUtils.h"
@@ skipping 56 matching lines @@
 
     stop = SkTMin(stop, record.count());
     SkRecords::Draw draw(canvas, drawablePicts, NULL, drawableCount, &initialCTM);
     for (unsigned i = start; i < stop; i++) {
         record.visit<void>(i, draw);
     }
 }
 
 namespace SkRecords {
 
-// FIXME: SkBitmaps are stateful, so we need to copy them to play back in multiple threads.
-static SkBitmap shallow_copy(const SkBitmap& bitmap) {
-    return bitmap;
-}
-
 // NoOps draw nothing.
 template <> void Draw::draw(const NoOp&) {}
 
 #define DRAW(T, call) template <> void Draw::draw(const T& r) { fCanvas->call; }
 DRAW(Restore, restore());
 DRAW(Save, save());
 DRAW(SaveLayer, saveLayer(r.bounds, r.paint, r.flags));
 DRAW(PopCull, popCull());
 DRAW(PushCull, pushCull(r.rect));
 DRAW(Clear, clear(r.color));
 DRAW(SetMatrix, setMatrix(SkMatrix::Concat(fInitialCTM, r.matrix)));
 
 DRAW(ClipPath, clipPath(r.path, r.opAA.op, r.opAA.aa));
 DRAW(ClipRRect, clipRRect(r.rrect, r.opAA.op, r.opAA.aa));
 DRAW(ClipRect, clipRect(r.rect, r.opAA.op, r.opAA.aa));
 DRAW(ClipRegion, clipRegion(r.region, r.op));
 
 DRAW(BeginCommentGroup, beginCommentGroup(r.description));
 DRAW(AddComment, addComment(r.key, r.value));
 DRAW(EndCommentGroup, endCommentGroup());
 
-DRAW(DrawBitmap, drawBitmap(shallow_copy(r.bitmap), r.left, r.top, r.paint));
-DRAW(DrawBitmapNine, drawBitmapNine(shallow_copy(r.bitmap), r.center, r.dst, r.paint));
+DRAW(DrawBitmap, drawBitmap(r.bitmap.shallowCopy(), r.left, r.top, r.paint));
+DRAW(DrawBitmapNine, drawBitmapNine(r.bitmap.shallowCopy(), r.center, r.dst, r.paint));
 DRAW(DrawBitmapRectToRect,
-        drawBitmapRectToRect(shallow_copy(r.bitmap), r.src, r.dst, r.paint,
+        drawBitmapRectToRect(r.bitmap.shallowCopy(), r.src, r.dst, r.paint,
                              SkCanvas::kNone_DrawBitmapRectFlag));
 DRAW(DrawBitmapRectToRectBleed,
-        drawBitmapRectToRect(shallow_copy(r.bitmap), r.src, r.dst, r.paint,
+        drawBitmapRectToRect(r.bitmap.shallowCopy(), r.src, r.dst, r.paint,
                              SkCanvas::kBleed_DrawBitmapRectFlag));
 DRAW(DrawDRRect, drawDRRect(r.outer, r.inner, r.paint));
 DRAW(DrawImage, drawImage(r.image, r.left, r.top, r.paint));
 DRAW(DrawImageRect, drawImageRect(r.image, r.src, r.dst, r.paint));
 DRAW(DrawOval, drawOval(r.oval, r.paint));
 DRAW(DrawPaint, drawPaint(r.paint));
 DRAW(DrawPath, drawPath(r.path, r.paint));
 DRAW(DrawPatch, drawPatch(r.cubics, r.colors, r.texCoords, r.xmode, r.paint));
 DRAW(DrawPicture, drawPicture(r.picture, &r.matrix, r.paint));
 DRAW(DrawPoints, drawPoints(r.mode, r.count, r.pts, r.paint));
 DRAW(DrawPosText, drawPosText(r.text, r.byteLength, r.pos, r.paint));
 DRAW(DrawPosTextH, drawPosTextH(r.text, r.byteLength, r.xpos, r.y, r.paint));
 DRAW(DrawRRect, drawRRect(r.rrect, r.paint));
 DRAW(DrawRect, drawRect(r.rect, r.paint));
-DRAW(DrawSprite, drawSprite(shallow_copy(r.bitmap), r.left, r.top, r.paint));
+DRAW(DrawSprite, drawSprite(r.bitmap.shallowCopy(), r.left, r.top, r.paint));
 DRAW(DrawText, drawText(r.text, r.byteLength, r.x, r.y, r.paint));
 DRAW(DrawTextBlob, drawTextBlob(r.blob, r.x, r.y, r.paint));
 DRAW(DrawTextOnPath, drawTextOnPath(r.text, r.byteLength, r.path, &r.matrix, r.paint));
 DRAW(DrawVertices, drawVertices(r.vmode, r.vertexCount, r.vertices, r.texs, r.colors,
                                 r.xmode.get(), r.indices, r.indexCount, r.paint));
 DRAW(DrawData, drawData(r.data, r.length));
 #undef DRAW
 
 template <> void Draw::draw(const DrawDrawable& r) {
     SkASSERT(r.index >= 0);
@@ skipping 660 matching lines @@
     SkRecords::CollectLayers visitor(cullRect, record, pictList, data);
 
     for (unsigned curOp = 0; curOp < record.count(); curOp++) {
         visitor.setCurrentOp(curOp);
         record.visit<void>(curOp, visitor);
     }
 
     visitor.cleanUp(bbh);
 }