Refactor cc scrollbar layers to separate solid-color vs desktop.

webkit/renderer/compositor_bindings/web_scrollbar_layer_impl.cc

 // Copyright 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.
 
 #include "webkit/renderer/compositor_bindings/web_scrollbar_layer_impl.h"
 
 #include "cc/layers/scrollbar_layer.h"
+#include "cc/layers/scrollbar_layer_base.h"
+#include "cc/layers/solid_color_scrollbar_layer.h"
 #include "third_party/WebKit/public/platform/WebScrollbar.h"
 #include "webkit/renderer/compositor_bindings/scrollbar_impl.h"
 #include "webkit/renderer/compositor_bindings/web_layer_impl.h"
 
 using cc::ScrollbarLayer;
+using cc::SolidColorScrollbarLayer;
+
+#if defined(OS_ANDROID)

[enne (OOO), 2013/08/12 23:15:01]

Please no platform #ifdefs.  Checking the setting for what kind of scrollbars to
create seems preferable.

[wjmaclean, 2013/08/14 18:19:44]

Fixed.

I now check an existing flag, --enable-overlay-scrollbars, which in ToT seems to
do what we want (though it's plumbed to Blink but doesn't seem to be used there,
so maybe a separate flag would be better?). I moved it's definition to
cc::switches so it would be available to web_scrollbar_layer_impl, let me know
if this is ok.

+namespace {
+
+cc::ScrollbarOrientation ConvertOrientation(
+    WebKit::WebScrollbar::Orientation orientation) {
+  return orientation == WebKit::WebScrollbar::Horizontal ? cc::HORIZONTAL
+                                                         : cc::VERTICAL;
+}
+
+const int kSolidColorScrollbarThumbThickness = 3;
+const SkColor kSolidColorScrollbarColor = SkColorSetARGB(128, 128, 128, 128);
+
+}  // namespace
+#endif
 
 namespace webkit {
 
 WebScrollbarLayerImpl::WebScrollbarLayerImpl(
     WebKit::WebScrollbar* scrollbar,
     WebKit::WebScrollbarThemePainter painter,
     WebKit::WebScrollbarThemeGeometry* geometry)
+#if defined(OS_ANDROID)
+    : layer_(new WebLayerImpl(SolidColorScrollbarLayer::Create(
+          ConvertOrientation(scrollbar->orientation()),
+          kSolidColorScrollbarThumbThickness,
+          kSolidColorScrollbarColor,
+          0))) {}
+#else
     : layer_(new WebLayerImpl(ScrollbarLayer::Create(
           scoped_ptr<cc::Scrollbar>(new ScrollbarImpl(
               make_scoped_ptr(scrollbar),
               painter,
               make_scoped_ptr(geometry))).Pass(), 0))) {}
+#endif
 
 WebScrollbarLayerImpl::~WebScrollbarLayerImpl() {}
 
 WebKit::WebLayer* WebScrollbarLayerImpl::layer() { return layer_.get(); }
 
 void WebScrollbarLayerImpl::setScrollLayer(WebKit::WebLayer* layer) {
   int id = layer ? static_cast<WebLayerImpl*>(layer)->layer()->id() : 0;
-  static_cast<ScrollbarLayer*>(layer_->layer())->SetScrollLayerId(id);
+  layer_->layer()->ToScrollbarLayerBase()->SetScrollLayerId(id);
 }
 
 }  // namespace webkit