Issue 600761  has been merged into this issue.

This is an unintended consequence of a change I made while reworking the buttons for MD. The fill will come as part of another change I need to make, which is having the background rounded rect fade-in/out as you mouse over the button ( issue 593531 ).

 Issue 610352  has been merged into this issue.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/9a51b633fca04015d122b763fd70ae216f65d30a

commit 9a51b633fca04015d122b763fd70ae216f65d30a
Author: shrike <shrike@chromium.org>
Date: Wed May 11 17:12:31 2016

[Mac][Material Design] Fix ghosting of cast and other extension icons.

Chrome Mac uses the ToolbarButton class to add extension buttons to the
toolbar, and calls setImage: to set the button's default image. However
under Material Design the ToolbarButton class sets images for several
states (e.g. hover, pressed) - the result is double-drawing of the
default icon. This cl changes ToolbarButton to store the setImage: icon
in an ivar, which prevents the double-drawing but also makes the icon
accessible for later use.

This cl also fixes a problem where the default icon could be drawn in
a different location for the default state than in the other states,
causing the icon to appear to shift as you mouse over the button.

R=avi@chromium.org
BUG= 593796 

Review-Url: https://codereview.chromium.org/1965193002
Cr-Commit-Position: refs/heads/master@{#392964}

[modify] https://crrev.com/9a51b633fca04015d122b763fd70ae216f65d30a/chrome/browser/ui/cocoa/toolbar/toolbar_button_cocoa.h
[modify] https://crrev.com/9a51b633fca04015d122b763fd70ae216f65d30a/chrome/browser/ui/cocoa/toolbar/toolbar_button_cocoa.mm