Move images from drawable-mdpi to drawable.

Not to fear, they're moved back to drawable-mdpi under the covers at
build time (https://chromiumcodereview.appspot.com/23944009), and the
apk is identical to before. The benefit: Android lint can find resources
that don't exist in all resolutions, and it's clearer what resolution
these mdpi images are.

BUG=289843
R=yfriedman@chromium.org

Review URL: https://codereview.chromium.org/26574005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@227821 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 227821
Remove obsolete webkit/tools/test_shell directory

All that was left here were a few resource files. Some of those did not
appear to be used, while the others already had duplicates available
in content/shell/resources.

R=jamesr
TBR=darin

Review URL: https://codereview.chromium.org/25351003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@227822 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 227822