[BlackBerry] Auth credentials set in private mode are reused in public mode.

[BlackBerry] Auth credentials set in private mode are reused in public mode.
https://bugs.webkit.org/show_bug.cgi?id=84697

Patch by Jason Liu <jason.liu@torchmobile.com.cn> on 2012-05-08
Reviewed by Rob Buis.

Add setPrivateMode function for CredentialStorage.

Source/WebCore:

Now, we only save credentials in memory and CredentialBackingStore isn't enabled.
When we set private mode from on to off, we clear all these temporary credentials.

We have to change Private Browsing to test, so have to write a manual test case.
Test: ManualTests/blackberry/http-auth-private-mode-changed.html

* network/CredentialStorage.cpp:
(WebCore::CredentialStorage::setPrivateMode):
(WebCore):
* platform/network/CredentialStorage.h:
(CredentialStorage):

Source/WebKit/blackberry:

We have to change Private Browsing to test, so have to write a manual test case.
Test: ManualTests/blackberry/http-auth-private-mode-changed.html

* Api/WebPage.cpp:
(BlackBerry::WebKit::WebPagePrivate::didChangeSettings):

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@116488 268f45cc-cd09-0410-ab3c-d52691b4dbfc