When possible, draw the toolbar shadow with the compositor

chrome/browser/android/compositor/scene_layer/toolbar_scene_layer.cc

Index: chrome/browser/android/compositor/scene_layer/toolbar_scene_layer.cc
diff --git a/chrome/browser/android/compositor/scene_layer/toolbar_scene_layer.cc b/chrome/browser/android/compositor/scene_layer/toolbar_scene_layer.cc
index 9a2de3934bc4ae18ee6dd41501687ffb0563c467..5afb21443868c76505a7985c209d7a382598fd9e 100644
--- a/chrome/browser/android/compositor/scene_layer/toolbar_scene_layer.cc
+++ b/chrome/browser/android/compositor/scene_layer/toolbar_scene_layer.cc
@@ -36,6 +36,7 @@ void ToolbarSceneLayer::UpdateToolbarLayer(
     const JavaParamRef<jobject>& object,
     const JavaParamRef<jobject>& jresource_manager,
     jint toolbar_resource_id,
+    jint toolbar_shadow_resource_id,
     jint toolbar_background_color,
     jint url_bar_resource_id,
     jfloat url_bar_alpha,
@@ -54,11 +55,11 @@ void ToolbarSceneLayer::UpdateToolbarLayer(
   toolbar_layer_->layer()->SetHideLayerAndSubtree(!visible);
   if (visible) {
     toolbar_layer_->layer()->SetPosition(gfx::PointF(0, top_offset));
-    // If we're at rest, hide the shadow.  The Android view should be drawing.
-    bool clip_shadow = top_offset >= 0.f && !show_shadow;
-    toolbar_layer_->PushResource(toolbar_resource_id, toolbar_background_color,
+    toolbar_layer_->PushResource(toolbar_resource_id,
+                                 toolbar_shadow_resource_id,
+                                 toolbar_background_color,
                                  false, SK_ColorWHITE, url_bar_resource_id,
-                                 url_bar_alpha, false, clip_shadow);
+                                 url_bar_alpha, false, show_shadow);
   }
 }