Update the host icons to the new style which includes the Chrome logo.
This affects all chromoting components, including the Android app and
the webapp.

All icons are based off the 512x512 PNG in the linked bug.

The smaller sizes were generated with ImageMagick, for example:
convert chromoting512.png -resize 48x48 chromoting48.png

ICO file was generated with:
convert chromoting16.png chromoting32.png chromoting48.png chromoting.ico

WebP versions were generated using cwebp:
for i in chromoting*.png; do \
  cwebp -lossless -q 100 -m 6 $i -o ${i%.png}.webp; done

Android empty_host_list icon was made by cropping 512x512 to 510x510,
then shrinking by a factor of 3, then converting to grayscale, then
darkening the image using GIMP and cropping to a few-pixels-wide
margin.

All PNGs were optimized by running:
tools/resources/optimize-png-files.sh -o2 remoting/resources

BUG=334830
R=jamiewalch@chromium.org

Review URL: https://codereview.chromium.org/222673002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@261530 0039d316-1c4b-4281-b951-d872f2087c98