NewRasterDirect should *not* erase the pixels -- direct means the client is in-charge

BUG=skia:
R=bsalomon@google.com

Author: reed@google.com

Review URL: https://codereview.chromium.org/246493002

git-svn-id: http://skia.googlecode.com/svn/trunk@14296 2bbb7eff-a529-9590-31e7-b0007b416f81

src/core/SkCanvas.cpp

@@ -2672,10 +2672,5 @@ SkCanvas* SkCanvas::NewRasterDirect(const SkImageInfo& info, void* pixels, size_
     if (!bitmap.installPixels(info, pixels, rowBytes)) {
         return NULL;
     }
-
-    // should this functionality be moved into allocPixels()?
-    if (!bitmap.info().isOpaque()) {
-        bitmap.eraseColor(0);
-    }
     return SkNEW_ARGS(SkCanvas, (bitmap));
 }