Plumb PinchVirtualViewport layers into CC.

cc/trees/layer_tree_host.cc

 // Copyright 2011 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/trees/layer_tree_host.h"
 
 #include <algorithm>
 #include <stack>
 
 #include "base/bind.h"
@@ skipping 312 matching lines @@
     sync_tree->set_hud_layer(static_cast<HeadsUpDisplayLayerImpl*>(hud_impl));
   } else {
     sync_tree->set_hud_layer(NULL);
   }
 
   sync_tree->set_background_color(background_color_);
   sync_tree->set_has_transparent_background(has_transparent_background_);
 
   sync_tree->FindRootScrollLayer();
 
+  // TODO(wjmaclean) For now, not all LTH clients will register viewports, so
+  // only set them when available..
+  if (page_scale_layer_) {
+    DCHECK(inner_viewport_scroll_layer_);
+    sync_tree->SetViewportLayersFromIds(
+        page_scale_layer_->id(),
+        inner_viewport_scroll_layer_->id(),
+        outer_viewport_scroll_layer_ ? outer_viewport_scroll_layer_->id()
+                                     : Layer::INVALID_ID);
+  } else {
+    sync_tree->ClearViewportLayers();
+  }
+
   float page_scale_delta, sent_page_scale_delta;
   if (settings_.impl_side_painting) {
     // Update the delta from the active tree, which may have
     // adjusted its delta prior to the pending tree being created.
     // This code is equivalent to that in LayerTreeImpl::SetPageScaleDelta.
     DCHECK_EQ(1.f, sync_tree->sent_page_scale_delta());
     page_scale_delta = host_impl->active_tree()->page_scale_delta();
     sent_page_scale_delta = host_impl->active_tree()->sent_page_scale_delta();
   } else {
     page_scale_delta = sync_tree->page_scale_delta();
@@ skipping 408 matching lines @@
   TRACE_EVENT1(benchmark_instrumentation::kCategory,
                benchmark_instrumentation::kLayerTreeHostUpdateLayers,
                benchmark_instrumentation::kSourceFrameNumber,
                source_frame_number());
 
   RenderSurfaceLayerList update_list;
   {
     UpdateHudLayer();
 
     Layer* root_scroll = FindFirstScrollableLayer(root_layer);
+    Layer* page_scale_layer = page_scale_layer_;
+    if (!page_scale_layer && root_scroll)
+      page_scale_layer = root_scroll->parent();
 
     if (hud_layer_) {
       hud_layer_->PrepareForCalculateDrawProperties(
           device_viewport_size(), device_scale_factor_);
     }
 
     TRACE_EVENT0("cc", "LayerTreeHost::UpdateLayers::CalcDrawProps");
     LayerTreeHostCommon::CalcDrawPropsMainInputs inputs(
         root_layer,
         device_viewport_size(),
         gfx::Transform(),
         device_scale_factor_,
         page_scale_factor_,
-        root_scroll ? root_scroll->parent() : NULL,
+        page_scale_layer,
         GetRendererCapabilities().max_texture_size,
         settings_.can_use_lcd_text,
         settings_.layer_transforms_should_scale_layer_contents,
         &update_list);
     LayerTreeHostCommon::CalculateDrawProperties(&inputs);
 
     if (total_frames_used_for_lcd_text_metrics_ <=
         kTotalFramesToUseForLCDTextMetrics) {
       LayerTreeHostCommon::CallFunctionForSubtree(
           root_layer,
@@ skipping 396 matching lines @@
     UIResourceRequest request;
     request.type = UIResourceRequest::UIResourceCreate;
     request.id = uid;
     bool resource_lost = true;
     request.bitmap = iter->second->GetBitmap(uid, resource_lost);
     DCHECK(request.bitmap.get());
     ui_resource_request_queue_.push_back(request);
   }
 }
 
+void LayerTreeHost::RegisterViewportLayers(
+    scoped_refptr<Layer> page_scale_layer,
+    scoped_refptr<Layer> inner_viewport_scroll_layer,
+    scoped_refptr<Layer> outer_viewport_scroll_layer) {
+  page_scale_layer_ = page_scale_layer;
+  inner_viewport_scroll_layer_ = inner_viewport_scroll_layer;
+  outer_viewport_scroll_layer_ = outer_viewport_scroll_layer;
+}
+
 }  // namespace cc