        - fixed the following bugs:         <rdar://problem/3584028>: Consider disallowing "View Source" for inline error pages         <rdar://problem/3584029>: "View Source" for inline error pages shows URL of "about:blank"         <rdar://problem/3584272>: Location field should be focused after a page-load error page is displayed         <rdar://problem/3586611>: REGRESSION (128): After option-pressing b/f button, selecting a menu item downloads it         - simplified some code
        - fixed the following bugs:
        <rdar://problem/3584028>: Consider disallowing "View Source" for inline error pages
        <rdar://problem/3584029>: "View Source" for inline error pages shows URL of "about:blank"
        <rdar://problem/3584272>: Location field should be focused after a page-load error page is displayed
        <rdar://problem/3586611>: REGRESSION (128): After option-pressing b/f button, selecting a menu item downloads it
        - simplified some code

        Reviewed by Chris.

        * BrowserDocument.h:
        * BrowserDocument.m:
        removed goBack: and goForward:; all callers now use these methods on
        BrowserWindowController instead.
        (-[BrowserDocument goToItemInBackOrForwardMenu:]):
        renamed from goToItem: for clarity, now ignores the Option key to avoid
        downloading when the user pressed Option to see URLs in the menu
        (-[BrowserDocument _addItem:toMenu:]):
        updated for name change
        (-[BrowserDocument canViewSource]):
        new method, extracted from validateUserInterfaceItem. Now also returns NO
        if the current page is an error page.
        (-[BrowserDocument validateUserInterfaceItem:]):
        now calls extracted method
        (-[BrowserDocument viewSource:]):
        now bails out early if canViewSource returns NO
        * BrowserWindowController.m:
        (-[BrowserWindowController webFrameLoadCommitted:]):
        if we're showing an error page now, move focus to location field (rather
        than webview as in the normal case)

        * Test/PageLoadTestRunner.m:
        (-[PageLoadTestRunner goBack]):
        call through browserWindowController; this was the only remaining caller of
        -[BrowserDocument goBack:] or -[BrowserDocument goForward:]


git-svn-id: bf5cd6ccde378db821296732a091cfbcf5285fbd@6218 bbb929c8-8fbe-4397-9dbb-9b2b20218538
primiano/blink-gitcs,primiano/blink-gitcs,primiano/blink-gitcs,primiano/blink-gitcs,primiano/blink-gitcs,primiano/blink-gitcs,primiano/blink-gitcs,primiano/blink-gitcs,primiano/blink-gitcs