Merge 175108 (for crbug.com/171096)

chrome/browser/ui/cocoa/tabs/tab_strip_controller.mm

 // Copyright (c) 2012 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.
 
 #import "chrome/browser/ui/cocoa/tabs/tab_strip_controller.h"
 
 #import <QuartzCore/QuartzCore.h>
 
 #include <cmath>
 #include <limits>
@@ skipping 178 matching lines @@
 
 // Takes a normal bitmap and a mask image and returns an image the size of the
 // mask that has pixels from |image| but alpha information from |mask|.
 NSImage* ApplyMask(NSImage* image, NSImage* mask) {
   return [CreateImageWithSize([mask size], ^(NSSize size) {
       // Skip a few pixels from the top of the tab background gradient, because
       // the new tab button is not drawn at the very top of the browser window.
       const int kYOffset = 10;
       CGFloat width = size.width;
       CGFloat height = size.height;
+
       // In some themes, the tab background image is narrower than the
       // new tab button, so tile the background image.
-      NSDrawThreePartImage(
-          NSMakeRect(0, -([image size].height - height - kYOffset),
-                     width, [image size].height),
-          nil, image, nil, /*vertical=*/NO, NSCompositeCopy,
-          1.0, /*flipped=*/NO);
+      CGFloat x = 0;
+      // The floor() is to make sure images with odd widths don't draw to the
+      // same pixel twice on retina displays. (Using NSDrawThreePartImage()
+      // caused a startup perf regression, so that cannot be used.)
+      CGFloat tileWidth = floor(std::min(width, [image size].width));
+      while (x < width) {
+        [image drawAtPoint:NSMakePoint(x, 0)
+                  fromRect:NSMakeRect(0,
+                                      [image size].height - height - kYOffset,
+                                      tileWidth,
+                                      height)
+                 operation:NSCompositeCopy
+                  fraction:1.0];
+        x += tileWidth;
+      }
+
       [mask drawAtPoint:NSZeroPoint
                fromRect:NSMakeRect(0, 0, width, height)
               operation:NSCompositeDestinationIn
                fraction:1.0];
   }) autorelease];
 }
 
 // Paints |overlay| on top of |ground|.
 NSImage* Overlay(NSImage* ground, NSImage* overlay, CGFloat alpha) {
   DCHECK_EQ([ground size].width, [overlay size].width);
@@ skipping 2003 matching lines @@
 NSView* GetSheetParentViewForWebContents(WebContents* web_contents) {
   // View hierarchy of the contents view:
   // NSView  -- switchView, same for all tabs
   // +- NSView  -- TabContentsController's view
   //    +- TabContentsViewCocoa
   //
   // Changing it? Do not forget to modify
   // -[TabStripController swapInTabAtIndex:] too.
   return [web_contents->GetNativeView() superview];
 }