Merge 147314 "Web Inspector: Fixed DOM Breakpoint pane styles."

Merge 147314 "Web Inspector: Fixed DOM Breakpoint pane styles."

> Web Inspector: Fixed DOM Breakpoint pane styles.
> https://bugs.webkit.org/show_bug.cgi?id=113688
> 
> Patch by Vladislav Kaznacheev <kaznacheev@chromium.org>; on 2013-04-01
> Reviewed by Pavel Feldman.
> 
> The required stylesheet (breakpointsList.css) was not loaded because of
> the peculiar way DOMBreakpointsSidebarPane is included in two panels
> (Sources and Elements) via a proxy pane. Since DOMBreakpointsSidebarPane
> was never shown directly the registerRequiredCSS call in its base class
> NativeBreakpointsSidebarPane constructor had no effect.
> Addin a registerRequiredCSS call to the proxy pane constructor fixes the
> problem.
> 
> * inspector/front-end/DOMBreakpointsSidebarPane.js:
> (WebInspector.DOMBreakpointsSidebarPane.Proxy):

TBR=commit-queue@webkit.org
Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=147735

[apavlov, 2013-04-05 10:12:49]

Committed patchset #1 manually as r147735.