A DCHECK was validating a little to widely, moved it into the if that needed ...

webkit/tools/test_shell/webwidget_host_win.cc

 // Copyright (c) 2006-2008 The Chromium Authors. All rights reserved...........
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "webkit/tools/test_shell/webwidget_host.h"
 
 #include "base/gfx/rect.h"
 #include "base/logging.h"
 #include "base/win_util.h"
 #include "skia/ext/platform_canvas.h"
@@ skipping 124 matching lines @@
     paint_rect_ = paint_rect_.Union(scroll_rect_);
     ResetScrollRect();
   }
   paint_rect_ = paint_rect_.Union(damaged_rect);
 
   RECT r = damaged_rect.ToRECT();
   InvalidateRect(view_, &r, FALSE);
 }
 
 void WebWidgetHost::DidScrollRect(int dx, int dy, const gfx::Rect& clip_rect) {
-  DCHECK(dx || dy);
+  if (dx != 0 && dy != 0) {
+    // We only support uni-directional scroll

[darin (slow to review), 2009/02/26 22:15:44]

ditto

+    DidScrollRect(0, dy, clip_rect);
+    dy = 0;
+  }
 
   // If we already have a pending scroll operation or if this scroll operation
   // intersects the existing paint region, then just failover to invalidating.
   if (!scroll_rect_.IsEmpty() || paint_rect_.Intersects(clip_rect)) {
     paint_rect_ = paint_rect_.Union(scroll_rect_);
     ResetScrollRect();
     paint_rect_ = paint_rect_.Union(clip_rect);
   }
 
   // We will perform scrolling lazily, when requested to actually paint.
@@ skipping 184 matching lines @@
 void WebWidgetHost::PaintRect(const gfx::Rect& rect) {
 #ifndef NDEBUG
   DCHECK(!painting_);
 #endif
   DCHECK(canvas_.get());
 
   set_painting(true);
   webwidget_->Paint(canvas_.get(), rect);
   set_painting(false);
 }