Revert of add peekPixels to SkCanvas and SkSurface (https://codereview.chromium.org/161733002/)

Reason for revert:
compile issues with gm/xfermodes3

Original issue's description:
> add peekPixels to SkCanvas and SkSurface
>
> clone of https://codereview.chromium.org/159723006/
>
> Committed: https://code.google.com/p/skia/source/detail?r=13427

R=jvanverth@google.com
NOTREECHECKS=true
NOTRY=true

Author: reed@chromium.org

Review URL: https://codereview.chromium.org/163823002

git-svn-id: http://skia.googlecode.com/svn/trunk@13428 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/samplecode/SampleLayers.cpp b/samplecode/SampleLayers.cpp
index bc8b873..483943d 100644
--- a/samplecode/SampleLayers.cpp
+++ b/samplecode/SampleLayers.cpp
@@ -42,10 +42,10 @@
     SkCanvas::LayerIter iter(canvas, true);
     int index = 0;
     while (!iter.done()) {
-        SkImageInfo info = iter.device()->imageInfo();
+        const SkBitmap& bm = iter.device()->accessBitmap(false);
         const SkIRect& clip = iter.clip().getBounds();
         SkDebugf("Layer[%d] bitmap [%d %d] X=%d Y=%d clip=[%d %d %d %d] alpha=%d\n", index++,
-                 info.width(), info.height(), iter.x(), iter.y(),
+                 bm.width(), bm.height(), iter.x(), iter.y(),
                  clip.fLeft, clip.fTop, clip.fRight, clip.fBottom,
                  iter.paint().getAlpha());
         iter.next();