diff -r 000000000000 -r dd21522fd290 webengine/osswebengine/WebKit/WebView/WebClipView.m
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/webengine/osswebengine/WebKit/WebView/WebClipView.m	Mon Mar 30 12:54:55 2009 +0300
@@ -0,0 +1,116 @@
+/*
+ * Copyright (C) 2005 Apple Computer, Inc.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1.  Redistributions of source code must retain the above copyright
+ *     notice, this list of conditions and the following disclaimer. 
+ * 2.  Redistributions in binary form must reproduce the above copyright
+ *     notice, this list of conditions and the following disclaimer in the
+ *     documentation and/or other materials provided with the distribution. 
+ * 3.  Neither the name of Apple Computer, Inc. ("Apple") nor the names of
+ *     its contributors may be used to endorse or promote products derived
+ *     from this software without specific prior written permission. 
+ *
+ * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
+ * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#import "WebClipView.h"
+
+#import <JavaScriptCore/Assertions.h>
+#import <WebKit/WebHTMLView.h>
+#import <WebKit/WebNSViewExtras.h>
+#import <WebKit/WebViewPrivate.h>
+
+// WebClipView's entire reason for existing is to set the clip used by focus ring redrawing.
+// There's no easy way to prevent the focus ring from drawing outside the passed-in clip rectangle
+// because it expects to have to draw outside the bounds of the view it's being drawn for.
+// But it looks for the enclosing clip view, which gives us a hook we can use to control it.
+// The "additional clip" is a clip for focus ring redrawing.
+
+// FIXME: Change terminology from "additional clip" to "focus ring clip".
+
+@interface NSView (WebViewMethod)
+- (WebView *)_webView;
+@end
+
+@implementation WebClipView
+
+- (id)initWithFrame:(NSRect)frame
+{
+    self = [super initWithFrame:frame];
+    if (!self)
+        return nil;
+    
+    // In WebHTMLView, we set a clip. This is not typical to do in an
+    // NSView, and while correct for any one invocation of drawRect:,
+    // it causes some bad problems if that clip is cached between calls.
+    // The cached graphics state, which clip views keep around, does
+    // cache the clip in this undesirable way. Consequently, we want to 
+    // release the GState for all clip views for all views contained in 
+    // a WebHTMLView. Here we do it for subframes, which use WebClipView.
+    // See these bugs for more information:
+    // <rdar://problem/3409315>: REGRESSSION (7B58-7B60)?: Safari draws blank frames on macosx.apple.com perf page
+    [self releaseGState];
+    
+    return self;
+}
+
+- (void)resetAdditionalClip
+{
+    ASSERT(_haveAdditionalClip);
+    _haveAdditionalClip = NO;
+}
+
+- (void)setAdditionalClip:(NSRect)additionalClip
+{
+    ASSERT(!_haveAdditionalClip);
+    _haveAdditionalClip = YES;
+    _additionalClip = additionalClip;
+}
+
+- (BOOL)hasAdditionalClip
+{
+    return _haveAdditionalClip;
+}
+
+- (NSRect)additionalClip
+{
+    ASSERT(_haveAdditionalClip);
+    return _additionalClip;
+}
+
+- (NSRect)_focusRingVisibleRect
+{
+    NSRect rect = [self visibleRect];
+    if (_haveAdditionalClip) {
+        rect = NSIntersectionRect(rect, _additionalClip);
+    }
+    return rect;
+}
+
+- (void)scrollWheel:(NSEvent *)event
+{
+    NSView *docView = [self documentView];
+    if ([docView respondsToSelector:@selector(_webView)]) {
+        WebView *wv = [docView _webView];
+        if ([wv _dashboardBehavior:WebDashboardBehaviorAllowWheelScrolling]) {
+            [super scrollWheel:event];
+        }
+        return;
+    }
+    [super scrollWheel:event];
+}
+
+@end