GC::saveLayer() may taint the current clip.

Source/platform/graphics/GraphicsContext.cpp

Index: Source/platform/graphics/GraphicsContext.cpp
diff --git a/Source/platform/graphics/GraphicsContext.cpp b/Source/platform/graphics/GraphicsContext.cpp
index 5f8fc1109c2669579e506d99d1ce31415100ce46..69cae52ea38d0d12fcb63c94c1742b96582aed76 100644
--- a/Source/platform/graphics/GraphicsContext.cpp
+++ b/Source/platform/graphics/GraphicsContext.cpp
@@ -179,14 +179,19 @@ void GraphicsContext::restore()
     m_canvas->restoreToCount(savedState.m_restoreCount);
 }
 
-void GraphicsContext::saveLayer(const SkRect* bounds, const SkPaint* paint, SkCanvas::SaveFlags saveFlags)
+void GraphicsContext::saveLayer(const SkRect* bounds, const SkPaint* paint,
+    SkCanvas::SaveFlags extraFlags)
 {
     if (paintingDisabled())
         return;
 
     realizeCanvasSave(SkCanvas::kMatrixClip_SaveFlag);
 
-    m_canvas->saveLayer(bounds, paint, saveFlags);
+    // Always save the clip & matrix.
+    SkCanvas::SaveFlags flags = static_cast<SkCanvas::SaveFlags>(
+        SkCanvas::kMatrixClip_SaveFlag | extraFlags);

[Stephen White, 2014/03/26 17:45:52]

Just an idea, but we could probably set these in the flags passed by
beginLayer() instead of here. The only calls to saveLayer() I can see other than
beginLayer() are from FEGaussianBlur and FEMorphology, which use the default arg
of kARGB_ClipLayer_SaveFlag anyway, which already includes matrix & clip. (Those
two should probably be calling beginLayer() anyway, then we can make saveLayer()
private.) Anyway, all that can be done in another patch.

[f(malita), 2014/03/26 19:31:28]

Done.

+    m_canvas->saveLayer(bounds, paint, flags);
+
     if (bounds)
         m_canvas->clipRect(*bounds);
     if (m_trackOpaqueRegion)