Bug 16828 – WebView never paints if first page load is canceled after being committed but before layout

• Component: WebKit Misc.
• Status: RESOLVED FIXED

[Adam Roben (:aroben)]

WebView never paints if the first page load is canceled after the load is committed but before the first layout occurs.

To reproduce:
1. Run a WebKit nightly <http://nightly.webkit.org/>
2. Set your Safari preferences to open new windows with a web page that loads slowly
3. Press Ctrl-N to create a new window
4. Quickly press Esc to cancel the load

The result is that the WebView portion of the Safari window never paints until you load a new page. Dragging another window over the WebView area leaves behind garbage pixels. Resizing the window doesn't help.

[Adam Roben (:aroben)]

The problem line of code seems to be this <http://trac.webkit.org/projects/webkit/browser/trunk/WebKit/win/WebView.cpp?rev=29369#L1590>:

            if (!webView->isPainting() && (!dataSource || coreFrame && (coreFrame->view()->didFirstLayout() || !coreFrame->loader()->committedFirstRealDocumentLoad())))

didFirstLayout() is returning false and committedFirstRealDocumentLoad() is returning true.

[Adam Roben (:aroben)]

<rdar://problem/5682402>

[Dave Hyatt]

firstLayout was a hack put in on Windows prior to having the full networking layer (with its notion of being "committed") ported over from Mac.  I suspect the firstLayout check is no longer needed (and does not match Mac anyway).

[Adam Roben (:aroben)]

Hyatt also says we should make sure the Windows and Mac agree on when painting should be suppressed.

[Adam Roben (:aroben)]

I have a fix for this.

[Adam Roben (:aroben)]

Created attachment 18399 [details]
patch 1/2

[Adam Roben (:aroben)]

Created attachment 18400 [details]
patch 2/2

[Dave Hyatt]

Comment on attachment 18399 [details]
patch 1/2

r=me

[Dave Hyatt]

Comment on attachment 18400 [details]
patch 2/2

r=me

[Adam Roben (:aroben)]

Landed as r29415 and r29416