use the userAgent() in the same loadable module as RendererWebKitPlatformSupportImpl

use the userAgent() in the same loadable module as RendererWebKitPlatformSupportImpl

In the component build, webkit_glue may be linked into multiple modules.
This can cause problems if we initialize the global variable in one
module but try to read it from others (which often happens in
browser_tests, where the WebKitPlatformSupport impl currently picks up
the version of glue linked into chrome.dll). This change ensures that callers
using content's default implementation of WebKitPlatformSupport will use
the correct instance of the function.

R=jam@chromium.org
BUG=90442
TEST=most browser_tests pass w/ content component build

Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=107501

[jam, 2011-10-25 23:47:59]

lgtm

[jam, 2011-10-25 23:47:59]

lgtm