Remove CPUProfileNode.visible from the protocol

The field is unused and just unnecessary overhead for the protocol messages.

BUG=None
R=alph@chromium.org

Review URL: https://codereview.chromium.org/21842004

git-svn-id: svn://svn.chromium.org/blink/trunk@155435 bbb929c8-8fbe-4397-9dbb-9b2b20218538
CSS Bg Blending fails when specifying background image and color separately

The problem is only visible when specifying an image known to be opaque using
background-image, followed by adding a background-color.
The fix consists of testing whether a blend mode is applied when checking
if the image is opaque.

BUG=266427

Review URL: https://chromiumcodereview.appspot.com/21742002

git-svn-id: svn://svn.chromium.org/blink/trunk@155436 bbb929c8-8fbe-4397-9dbb-9b2b20218538