[Mac] Don't paint linen pattern when contents size is not available.

This was causing auto-complete popup windows to have their contents always overpainted by the linen texture, since contents_size was empty for them.

BUG=92645
TEST=see bug

Review URL: http://codereview.chromium.org/7640018

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@96594 0039d316-1c4b-4281-b951-d872f2087c98

chrome/browser/renderer_host/render_widget_host_view_mac.mm

@@ -1640,6 +1640,11 @@ void RenderWidgetHostViewMac::SetTextInputActive(bool active) {
   if (![NSColor respondsToSelector:@selector(_linenPatternImage)])
     return;
 
+  // Don't paint over-scroll areas if |contents_size| is empty, which indicates
+  // that the render widget is not a RenderView.
+  if (renderWidgetHostView_->render_widget_host_->contents_size().IsEmpty())
+    return;
+
   NSRect visibleContentRect = [self computeVisibleContentRect];
   NSSize frameSize = [self frame].size;
   bool hasHorizontalOverflow = (NSWidth(visibleContentRect) < frameSize.width);