use AutoRestore instead of making a copy of the clipstack

BUG=skia:

Change-Id: I86683156926f7c63c83790eaf313112ba5fab763
Reviewed-on: https://skia-review.googlesource.com/9532
Reviewed-by: Florin Malita <fmalita@chromium.org>
Commit-Queue: Mike Reed <reed@google.com>

1 files changed, 8 insertions, 14 deletions

diff --git a/src/svg/SkSVGDevice.cpp b/src/svg/SkSVGDevice.cpp
index 7ce616436c..91ebadb7f0 100644
--- a/src/svg/SkSVGDevice.cpp
+++ b/src/svg/SkSVGDevice.cpp
@@ -278,10 +278,8 @@ struct SkSVGDevice::MxCp {
     const SkMatrix* fMatrix;
     const SkClipStack*  fClipStack;
 
-    MxCp(SkSVGDevice* device) {
-        fMatrix = &device->ctm();
-        fClipStack = &device->cs();
-    }
+    MxCp(const SkMatrix* mx, const SkClipStack* cs) : fMatrix(mx), fClipStack(cs) {}
+    MxCp(SkSVGDevice* device) : fMatrix(&device->ctm()), fClipStack(&device->cs()) {}
 };
 
 class SkSVGDevice::AutoElement : ::SkNoncopyable {
@@ -729,24 +727,20 @@ void SkSVGDevice::drawSprite(const SkBitmap& bitmap,
 void SkSVGDevice::drawBitmapRect(const SkBitmap& bm, const SkRect* srcOrNull,
                                  const SkRect& dst, const SkPaint& paint,
                                  SkCanvas::SrcRectConstraint) {
-    MxCp mc(this);
-
-    SkClipStack adjustedClipStack;
+    SkClipStack* cs = &this->cs();
+    SkClipStack::AutoRestore ar(cs, false);
     if (srcOrNull && *srcOrNull != SkRect::Make(bm.bounds())) {
-        adjustedClipStack = *mc.fClipStack;
-        adjustedClipStack.clipRect(dst, *mc.fMatrix, kIntersect_SkClipOp,
-                                   paint.isAntiAlias());
-        mc.fClipStack = &adjustedClipStack;
+        cs->save();
+        cs->clipRect(dst, this->ctm(), kIntersect_SkClipOp, paint.isAntiAlias());
     }
 
     SkMatrix adjustedMatrix;
     adjustedMatrix.setRectToRect(srcOrNull ? *srcOrNull : SkRect::Make(bm.bounds()),
                                  dst,
                                  SkMatrix::kFill_ScaleToFit);
-    adjustedMatrix.postConcat(*mc.fMatrix);
-    mc.fMatrix = &adjustedMatrix;
+    adjustedMatrix.postConcat(this->ctm());
 
-    drawBitmapCommon(mc, bm, paint);
+    drawBitmapCommon(MxCp(&adjustedMatrix, cs), bm, paint);
 }
 
 void SkSVGDevice::drawText(const void* text, size_t len,