Add flag for drawing layers to screen with Ganesh

cc/layers/picture_layer_impl.cc

Index: cc/layers/picture_layer_impl.cc
diff --git a/cc/layers/picture_layer_impl.cc b/cc/layers/picture_layer_impl.cc
index 3d6188711e5b5d109ced38efb7226fc58981080a..777488e6bbde86d48125ad9658a8f5b96bd29b5f 100644
--- a/cc/layers/picture_layer_impl.cc
+++ b/cc/layers/picture_layer_impl.cc
@@ -119,8 +119,14 @@ void PictureLayerImpl::AppendQuads(QuadSink* quad_sink,
           color = DebugColors::SolidColorTileBorderColor();
           width = DebugColors::SolidColorTileBorderWidth(layer_tree_impl());
         } else if (mode == ManagedTileState::DrawingInfo::PICTURE_PILE_MODE) {
-          color = DebugColors::PictureTileBorderColor();
-          width = DebugColors::PictureTileBorderWidth(layer_tree_impl());
+          if (CanDrawDirectlyToBackbuffer()) {
+            color = DebugColors::DirectPictureTileBorderColor();
+            width =
+                DebugColors::DirectPictureTileBorderWidth(layer_tree_impl());
+          } else {
+            color = DebugColors::PictureTileBorderColor();
+            width = DebugColors::PictureTileBorderWidth(layer_tree_impl());
+          }
         } else if (iter->priority(ACTIVE_TREE).resolution == HIGH_RESOLUTION) {
           color = DebugColors::HighResTileBorderColor();
           width = DebugColors::HighResTileBorderWidth(layer_tree_impl());
@@ -148,6 +154,25 @@ void PictureLayerImpl::AppendQuads(QuadSink* quad_sink,
     }
   }
 
+  if (CanDrawDirectlyToBackbuffer() &&
+      layer_tree_impl()->settings().always_use_skpicture_layers) {
+    scoped_ptr<PictureDrawQuad> quad = PictureDrawQuad::Create();
+    gfx::Rect opaque_rect;
+    quad->SetNew(shared_quad_state,
+                 content_rect,
+                 opaque_rect,
+                 gfx::RectF(0, 0, 1, 1),
+                 content_rect.size(),
+                 false,
+                 content_rect,
+                 contents_scale_x(),
+                 CanDrawDirectlyToBackbuffer(),
+                 pile_);
+    if (quad_sink->Append(quad.PassAs<DrawQuad>(), append_quads_data))
+      append_quads_data->num_missing_tiles++;
+    return;
+  }
+
   // Keep track of the tilings that were used so that tilings that are
   // unused can be considered for removal.
   std::vector<PictureLayerTiling*> seen_tilings;
@@ -228,6 +253,7 @@ void PictureLayerImpl::AppendQuads(QuadSink* quad_sink,
                      drawing_info.contents_swizzled(),
                      iter->content_rect(),
                      iter->contents_scale(),
+                     CanDrawDirectlyToBackbuffer(),
                      pile_);
         quad_sink->Append(quad.PassAs<DrawQuad>(), append_quads_data);
         break;
@@ -347,6 +373,19 @@ void PictureLayerImpl::CalculateContentsScale(
   ideal_device_scale_ = ideal_device_scale;
   ideal_source_scale_ = std::max(ideal_source_scale, min_source_scale);
 
+  if (CanDrawDirectlyToBackbuffer() &&
+      layer_tree_impl()->settings().always_use_skpicture_layers) {
+    if (tilings_)
+      tilings_->RemoveAllTilings();
+
+    *contents_scale_x = ideal_contents_scale_;
+    *contents_scale_y = ideal_contents_scale_;
+    *content_bounds = gfx::ToCeiledSize(gfx::ScaleSize(bounds(),
+                                                       ideal_contents_scale_,
+                                                       ideal_contents_scale_));
+    return;
+  }
+
   ManageTilings(animating_transform_to_screen);
 
   // The content scale and bounds for a PictureLayerImpl is somewhat fictitious.
@@ -547,6 +586,9 @@ bool PictureLayerImpl::AreVisibleResourcesReady() const {
   DCHECK(layer_tree_impl()->IsPendingTree());
   DCHECK(ideal_contents_scale_);
 
+  if (!tilings_->num_tilings())
+    return true;
+
   gfx::Rect rect(visible_content_rect());
 
   float min_acceptable_scale =