Allow background tab titles to use LCD AA.

cc/blink/web_display_item_list_impl.cc

 // Copyright 2014 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 "cc/blink/web_display_item_list_impl.h"
 
 #include <vector>
 
 #include "cc/blink/web_filter_operations_impl.h"
 #include "cc/playback/clip_display_item.h"
@@ skipping 150 matching lines @@
     const blink::WebRect& visual_rect,
     float opacity,
     SkXfermode::Mode xfermode,
     SkRect* bounds,
     SkColorFilter* color_filter) {
   DCHECK_GE(opacity, 0.f);
   DCHECK_LE(opacity, 1.f);
   // TODO(ajuma): This should really be rounding instead of flooring the alpha
   // value, but that breaks slimming paint reftests.
 
+  const bool kLcdTextRequiresOpaqueLayer = true;
   if (display_item_list_->RetainsIndividualDisplayItems()) {
     display_item_list_->CreateAndAppendItem<cc::CompositingDisplayItem>(
         visual_rect, static_cast<uint8_t>(gfx::ToFlooredInt(255 * opacity)),
-        xfermode, bounds, skia::SharePtr(color_filter));
+        xfermode, bounds, skia::SharePtr(color_filter),
+        kLcdTextRequiresOpaqueLayer);
   } else {
     cc::CompositingDisplayItem item(
         static_cast<uint8_t>(gfx::ToFlooredInt(255 * opacity)), xfermode,
-        bounds, skia::SharePtr(color_filter));
+        bounds, skia::SharePtr(color_filter), kLcdTextRequiresOpaqueLayer);
     display_item_list_->RasterIntoCanvas(item);
   }
 }
 
 void WebDisplayItemListImpl::appendEndCompositingItem(
     const blink::WebRect& visual_rect) {
   if (display_item_list_->RetainsIndividualDisplayItems()) {
     display_item_list_->CreateAndAppendItem<cc::EndCompositingDisplayItem>(
         visual_rect);
   } else {
@@ skipping 39 matching lines @@
 
 void WebDisplayItemListImpl::appendEndScrollItem(
     const blink::WebRect& visual_rect) {
   appendEndTransformItem(visual_rect);
 }
 
 WebDisplayItemListImpl::~WebDisplayItemListImpl() {
 }
 
 }  // namespace cc_blink