add peekPixels to SkCanvas and SkSurface

fix reference to SkBaseDevice, which was only a problem in no-gpu build

This reverts commit 4fa44a6bf73891b21917fb90d02beef9143bffa3.

R=reed@google.com

Author: reed@chromium.org

Review URL: https://codereview.chromium.org/163603003

git-svn-id: http://skia.googlecode.com/svn/trunk@13432 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/gm/displacement.cpp b/gm/displacement.cpp
index ef6207a..b1f097b 100644
--- a/gm/displacement.cpp
+++ b/gm/displacement.cpp
@@ -33,8 +33,7 @@
 
     void make_bitmap() {
         fBitmap.allocN32Pixels(80, 80);
-        SkBitmapDevice device(fBitmap);
-        SkCanvas canvas(&device);
+        SkCanvas canvas(fBitmap);
         canvas.clear(0x00000000);
         SkPaint paint;
         paint.setAntiAlias(true);
@@ -46,8 +45,7 @@
 
     void make_checkerboard(SkBitmap* bitmap, int w, int h) {
         bitmap->allocN32Pixels(w, h);
-        SkBitmapDevice device(*bitmap);
-        SkCanvas canvas(&device);
+        SkCanvas canvas(*bitmap);
         canvas.clear(0x00000000);
         SkPaint darkPaint;
         darkPaint.setColor(0xFF804020);