Allow background tab titles to use LCD AA.

cc/blink/web_display_item_list_impl.cc

Index: cc/blink/web_display_item_list_impl.cc
diff --git a/cc/blink/web_display_item_list_impl.cc b/cc/blink/web_display_item_list_impl.cc
index 9859d1c39ab4782af2b9d188a8aaad336593f6d3..f5d89b0e6e921075b9c247a080f9bfe3522bed99 100644
--- a/cc/blink/web_display_item_list_impl.cc
+++ b/cc/blink/web_display_item_list_impl.cc
@@ -168,14 +168,16 @@ void WebDisplayItemListImpl::appendCompositingItem(
   // TODO(ajuma): This should really be rounding instead of flooring the alpha
   // value, but that breaks slimming paint reftests.
 
+  const bool kLcdTextRequiresOpaqueLayer = true;

[danakj, 2015/12/11 22:44:02]

fwiw, i would normally write this as

bool lcd_text_requires_opaque_layer = true;

i mean, this is fine and all, just saying in case you like that.

[Peter Kasting, 2015/12/12 02:51:55]

Yeah, an argument can be made for each -- is this a boolean variable whose value
doesn't change?  Or is it a named constant?  I went with the latter.

   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);
   }
 }