Use a widget as drag icon for proper transparency handling.
Use a widget as drag icon for proper transparency handling.

gtk_drag_set_icon_pixbuf converts pixbuf with alpha into a pixmap and mask.
It uses the pixmap as window back pixmap and shape the window with the mask.
This should work theoretically. However, the underlying window's content
get mixed into the drag icon and make it un-usable. So changing to use a
drag icon widget of our own which would render everything correctly.

BUG=none.
TEST=Verify the drag-n-drop works correct without a messed up drag icon on bookmark bar and omnibox.

Review URL: http://codereview.chromium.org/1630017

git-svn-id: de016e52bd170d2d4f2344f9bf92d50478b649e0@44483 0039d316-1c4b-4281-b951-d872f2087c98

Crystalnix/house-of-life-chromium,yitian134/chromium,yitian134/chromium,yitian134/chromium,adobe/chromium,Crystalnix/house-of-life-chromium,yitian134/chromium,gavinp/chromium,ropik/chromium,gavinp/chromium,Crystalnix/house-of-life-chromium,yitian134/chromium,adobe/chromium,yitian134/chromium,Crystalnix/house-of-life-chromium,adobe/chromium,adobe/chromium,adobe/chromium,ropik/chromium,gavinp/chromium,adobe/chromium,gavinp/chromium,adobe/chromium,yitian134/chromium,adobe/chromium,adobe/chromium,Crystalnix/house-of-life-chromium,gavinp/chromium,Crystalnix/house-of-life-chromium,yitian134/chromium,Crystalnix/house-of-life-chromium,Crystalnix/house-of-life-chromium,ropik/chromium,ropik/chromium,ropik/chromium,gavinp/chromium,Crystalnix/house-of-life-chromium,gavinp/chromium,yitian134/chromium,Crystalnix/house-of-life-chromium,ropik/chromium,Crystalnix/house-of-life-chromium,gavinp/chromium,ropik/chromium,yitian134/chromium,ropik/chromium,gavinp/chromium,gavinp/chromium,adobe/chromium,adobe/chromium,ropik/chromium