Inconsistent use of [x] close panel icon. Code changes.

Inconsistent use of [x] close panel icon.
The close button in download pane should be the tab close button asset : tab_close_*.png (this was originally reported as part of BUG=173251
).

By the same logic the same smaller bitmap with red hover background should be used for all infobars
such as translate bar, save password bar, etc. It should also be used for find-in-page bar on all
platforms (Mac was missed with the previous implementation).

The close button in the chrome UI and Web UI bubbles was left the same as before (this needs to be regression-tested).

Code was rearranged to make explicit the discrepancy between the IDR_CLOSE_BAR and IDR_CLOSE_BUBBLE.
IDR_TAB_CLOSE was renamed IDR_CLOSE_1.
IDR_CLOSE_BAR was renamed IDR_CLOSE_2.
png files were also renamed (this is handled by two separate committs to work around restriction on binary committs by newbies).
See https://codereview.chromium.org/12703022/ for added resources.

BUG=217094
TEST=Open any page that downloads an attachment such as gmail email with an attachment or a page with images. Download an image or an attachment. Verify that the close button in download bar at the bottom of the screen has a red circular background when mouse hovers over it - same as the close tab button.

TEST=Open find-in-page (Ctrl+F) box on Mac, Linux and Windows and check that the close button is same as tab close (has a red circular background when mouse hovers over it).

TEST=Open any infobar (translate / save password) on both ChromeOS and linux and check that the close button is same as tab close (has a red circular background when mouse hovers over it). Opening a non-English news page is usually the easiest way.

TEST=Trigger chrome to show a toolbar bubble such as extension installed bubble that shows when an extension is installed from chrome web store (see bitmaps in comments attached to BUG=217094
). Confirm that the close buttons in those bubbles are NOT changed from before the change (they should NOT have the red circular background when mouse hovers over).

[commit-bot: I haz the power, 2013-03-25 21:53:32]

No reviewers yet.

[varkha, 2013-03-25 21:58:21]

This had been reviewed but broke build on a few configurations. It is now being
committed in 3 steps (add resources, commit code changes via a bot and then
delete old images.
See original complete diffs at https://codereview.chromium.org/12634025/