cc/paint: Remove cc::PaintSurface.

cc/paint/skia_paint_canvas.cc

Index: cc/paint/skia_paint_canvas.cc
diff --git a/cc/paint/skia_paint_canvas.cc b/cc/paint/skia_paint_canvas.cc
index fa90ec0f01c7b34630943a0c1c0d9a11b0c0828f..227389b5829716c7143eec295bc691adc18e27c5 100644
--- a/cc/paint/skia_paint_canvas.cc
+++ b/cc/paint/skia_paint_canvas.cc
@@ -9,11 +9,25 @@
 #include "cc/paint/paint_record.h"
 #include "cc/paint/paint_recorder.h"
 #include "third_party/skia/include/core/SkAnnotation.h"
+#include "third_party/skia/include/core/SkMallocPixelRef.h"
 #include "third_party/skia/include/core/SkMetaData.h"
 #include "third_party/skia/include/utils/SkNWayCanvas.h"
 
 namespace cc {
 
+// static
+std::unique_ptr<SkiaPaintCanvas> SkiaPaintCanvas::CreateRasterZeroed(

[enne (OOO), 2017/03/22 00:41:01]

I'm a little confused about the zeroed part of this.  Is that new?  Over what
the code used to do?

[Khushal, 2017/03/22 00:45:51]

The SkSurface does that, and I had a few tests breaking without it so I assumed
some code that was using gfx::Canvas was relying on it?

I can change call-sites of this function to create a bitmap directly. And only
have the gfx one use zero initialization.

[danakj, 2017/03/22 15:06:51]

Can you just have code that makes SkBitmap call SkCanvas::clear() on it directly
if not opaque?

+    const SkImageInfo& info) {
+  sk_sp<SkPixelRef> pr(SkMallocPixelRef::NewZeroed(info, 0, nullptr));
+  if (!pr)
+    return nullptr;
+
+  SkBitmap bitmap;
+  bitmap.setInfo(info, pr->rowBytes());
+  bitmap.setPixelRef(std::move(pr), 0, 0);
+  return base::MakeUnique<SkiaPaintCanvas>(bitmap);
+}
+
 SkiaPaintCanvas::SkiaPaintCanvas(SkCanvas* canvas) : canvas_(canvas) {}
 
 SkiaPaintCanvas::SkiaPaintCanvas(const SkBitmap& bitmap)