Putting the findbar into a child window.

chrome/browser/cocoa/background_gradient_view.mm

 // Copyright (c) 2009 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 "chrome/browser/cocoa/background_gradient_view.h"
 
 #import "chrome/browser/browser_theme_provider.h"
 #import "chrome/browser/cocoa/themed_window.h"
 #include "grit/theme_resources.h"
 
@@ skipping 13 matching lines @@
 
 - (void)awakeFromNib {
   showsDivider_ = YES;
 }
 
 - (void)setShowsDivider:(BOOL)show {
   showsDivider_ = show;
   [self setNeedsDisplay:YES];
 }
 
+- (BOOL)drawsAsKey {
+  return [[self window] isKeyWindow];
+}
+
 - (void)drawBackground {
-  BOOL isKey = [[self window] isKeyWindow];
+  BOOL isKey = [self drawsAsKey];
   ThemeProvider* themeProvider = [[self window] themeProvider];
   if (themeProvider) {
     NSColor* backgroundImageColor =
         themeProvider->GetNSImageColorNamed(IDR_THEME_TOOLBAR, false);
     if (backgroundImageColor) {
       [backgroundImageColor set];
       NSRectFill([self bounds]);
     } else {
       CGFloat winHeight = NSHeight([[self window] frame]);
+      if ([[self window] parentWindow])
+        winHeight = NSHeight([[[self window] parentWindow] frame]);
       NSGradient* gradient = themeProvider->GetNSGradient(
           isKey ? BrowserThemeProvider::GRADIENT_TOOLBAR :
                   BrowserThemeProvider::GRADIENT_TOOLBAR_INACTIVE);
       NSPoint startPoint =
           [self convertPoint:NSMakePoint(0, winHeight - kToolbarTopOffset)
                     fromView:nil];
       NSPoint endPoint =
           NSMakePoint(0, winHeight - kToolbarTopOffset - kToolbarMaxHeight);
       endPoint = [self convertPoint:endPoint fromView:nil];
 
       [gradient drawFromPoint:startPoint
                       toPoint:endPoint
                       options:(NSGradientDrawsBeforeStartingLocation |
                                NSGradientDrawsAfterEndingLocation)];
     }
 
     if (showsDivider_) {
       // Draw bottom stroke
       [[self strokeColor] set];
       NSRect borderRect, contentRect;
       NSDivideRect([self bounds], &borderRect, &contentRect, 1, NSMinYEdge);
       NSRectFillUsingOperation(borderRect, NSCompositeSourceOver);
     }
   }
 }
 
 - (NSColor*)strokeColor {
-  BOOL isKey = [[self window] isKeyWindow];
+  BOOL isKey = [self drawsAsKey];
   ThemeProvider* themeProvider = [[self window] themeProvider];
   if (!themeProvider)
     return [NSColor blackColor];
   return themeProvider->GetNSColor(
       isKey ? BrowserThemeProvider::COLOR_TOOLBAR_STROKE :
               BrowserThemeProvider::COLOR_TOOLBAR_STROKE_INACTIVE, true);
 }
 
 @end