REGRESSION (r167856): adobe.com no longer able to launch Create Cloud app using a URL with a custom scheme
https://bugs.webkit.org/show_bug.cgi?id=136010

Reviewed by Darin Adler.

Source/WebCore:

r167856 caused WebKit to stop scheduling certain kinds of navigations (window.location changes, meta-refresh,
and some calls to window.open) when the request URL is invalid. Adobe.com performs one of these navigations to
an invalid URL with an external scheme (aam:), relying on Safari's navigation policy delegate to ignore the
navigation and launch the external app registered to handle aam: URLs. Since the navigation is no longer
scheduled, the policy delegate is never executed and the external app never launches.

Instead of not scheduling the navigation, allow it to proceed until the client's policy delegate has executed
and made a decision. Only disallow the navigation if the policy delegate told WebKit to proceed with the load.
This exposes these navigations to clients via the policy delegate and via willPerformClientRedirectToURL and
didCancelClientRedirectForFrame on the frame load delegate.

Note that r167856 also caused an iOS regression, and this was resolved in r170120 by adding a linked-on-or-after
check and a WebCore setting. Since the iOS regression is also resolved by the approach described above, this
patch reverts r170120 (but keeps some of its tests).

Tests: fast/loader/redirect-to-invalid-url-using-javascript-calls-policy-delegate.html
       fast/loader/redirect-to-invalid-url-using-javascript-disallowed.html
       fast/loader/redirect-to-invalid-url-using-meta-refresh-calls-policy-delegate.html
       fast/loader/redirect-to-invalid-url-using-meta-refresh-disallowed.html
       fast/loader/window-open-to-invalid-url-calls-policy-delegate.html
       fast/loader/window-open-to-invalid-url-disallowed.html

* loader/FrameLoader.cpp:
(WebCore::FrameLoader::continueLoadAfterNavigationPolicy): Do not continue if the navigation will be a redirect
to an invalid URL.
* loader/NavigationScheduler.cpp:
(WebCore::NavigationScheduler::shouldScheduleNavigation): Resumed scheduling navigations to invalid URLs.
* page/Settings.in: Removed the allowNavigationToInvalidURL setting.

Source/WebKit/mac:

Reverted the linked-on-or-after check added in r170120 since it is no longer necessary.

* Misc/WebKitVersionChecks.h:
* WebView/WebView.mm:
(-[WebView _preferencesChanged:]):

LayoutTests:

Removed tests that verified the behavior of setAllowNavigationToInvalidURL(true), which no longer exists:
* fast/loader/allow-redirect-to-invalid-url-using-javascript-expected.txt: Removed.
* fast/loader/allow-redirect-to-invalid-url-using-javascript.html: Removed.
* fast/loader/allow-redirect-to-invalid-url-using-meta-refresh-expected.txt: Removed.
* fast/loader/allow-redirect-to-invalid-url-using-meta-refresh.html: Removed.

Added tests that verify the policy delegate is executed on some navigations to invalid URLs:
* fast/loader/redirect-to-invalid-url-using-javascript-calls-policy-delegate-expected.txt: Added.
* fast/loader/redirect-to-invalid-url-using-javascript-calls-policy-delegate.html: Added.
* fast/loader/redirect-to-invalid-url-using-meta-refresh-calls-policy-delegate-expected.txt: Added.
* fast/loader/redirect-to-invalid-url-using-meta-refresh-calls-policy-delegate.html: Added.
* fast/loader/window-open-to-invalid-url-calls-policy-delegate-expected.txt: Added.
* fast/loader/window-open-to-invalid-url-calls-policy-delegate.html: Added.

Renamed some existing tests added in r170120, modified them to log willPerformClientRedirectToURL and
didCancelClientRedirectForFrame, and added a test to verify navigations in existing frames via window.open:
* fast/loader/redirect-to-invalid-url-using-javascript-disallowed-expected.txt: Renamed from fast/loader/disallow-redirect-to-invalid-url-using-javascript-expected.txt.
* fast/loader/redirect-to-invalid-url-using-javascript-disallowed.html: Renamed from fast/loader/disallow-redirect-to-invalid-url-using-javascript.html.
* fast/loader/redirect-to-invalid-url-using-meta-refresh-disallowed-expected.txt: Renamed from fast/loader/disallow-redirect-to-invalid-url-using-meta-refresh-expected.txt.
* fast/loader/redirect-to-invalid-url-using-meta-refresh-disallowed.html: Renamed from fast/loader/disallow-redirect-to-invalid-url-using-meta-refresh.html.
* fast/loader/window-open-to-invalid-url-disallowed-expected.txt: Added.
* fast/loader/window-open-to-invalid-url-disallowed.html: Added.

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@172697 268f45cc-cd09-0410-ab3c-d52691b4dbfc