Add a |scope| argument to TRACE_EVENT_INSTANT* and require its presence.

cc/layer_tree_host_common.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/layer_tree_host_common.h"
 
 #include <algorithm>
 
 #include "base/debug/trace_event.h"
 #include "cc/heads_up_display_layer_impl.h"
@@ skipping 268 matching lines @@
 
     // If the layer uses a CSS filter.
     if (!layer->filters().isEmpty() || !layer->backgroundFilters().isEmpty() || layer->filter())
         return true;
 
     int numDescendantsThatDrawContent = layer->drawProperties().num_descendants_that_draw_content;
 
     // If the layer flattens its subtree (i.e. the layer doesn't preserve-3d), but it is
     // treated as a 3D object by its parent (i.e. parent does preserve-3d).
     if (layerIsInExisting3DRenderingContext(layer) && !layer->preserves3D() && numDescendantsThatDrawContent > 0) {
-        TRACE_EVENT_INSTANT0("cc", "LayerTreeHostCommon::requireSurface flattening");
+        TRACE_EVENT_INSTANT0("cc", "LayerTreeHostCommon::requireSurface flattening",
+                             TRACE_EVENT_SCOPE_THREAD);
         return true;
     }
 
     // If the layer clips its descendants but it is not axis-aligned with respect to its parent.
     bool layerClipsExternalContent = layerClipsSubtree(layer) || layer->hasDelegatedContent();
     if (layerClipsExternalContent && !axisAlignedWithRespectToParent && !layer->drawProperties().descendants_can_clip_selves)
     {
-        TRACE_EVENT_INSTANT0("cc", "LayerTreeHostCommon::requireSurface clipping");
+        TRACE_EVENT_INSTANT0("cc", "LayerTreeHostCommon::requireSurface clipping",
+                             TRACE_EVENT_SCOPE_THREAD);
         return true;
     }
 
     // If the layer has some translucency and does not have a preserves-3d transform style.
     // This condition only needs a render surface if two or more layers in the
     // subtree overlap. But checking layer overlaps is unnecessarily costly so
     // instead we conservatively create a surface whenever at least two layers
     // draw content for this subtree.
     bool atLeastTwoLayersInSubtreeDrawContent = numDescendantsThatDrawContent > 0 && (layer->drawsContent() || numDescendantsThatDrawContent > 1);
 
     if (layer->opacity() != 1 && !layer->preserves3D() && atLeastTwoLayersInSubtreeDrawContent) {
-        TRACE_EVENT_INSTANT0("cc", "LayerTreeHostCommon::requireSurface opacity");
+        TRACE_EVENT_INSTANT0("cc", "LayerTreeHostCommon::requireSurface opacity",
+                             TRACE_EVENT_SCOPE_THREAD);
         return true;
     }
 
     return false;
 }
 
 gfx::Transform computeScrollCompensationForThisLayer(LayerImpl* scrollingLayer, const gfx::Transform& parentMatrix)
 {
     // For every layer that has non-zero scrollDelta, we have to compute a transform that can undo the
     // scrollDelta translation. In particular, we want this matrix to premultiply a fixed-position layer's
@@ skipping 882 matching lines @@
 
   // At this point, we think the point does hit the touch event handler region on the layer, but we need to walk up
   // the parents to ensure that the layer was not clipped in such a way that the
   // hit point actually should not hit the layer.
   if (pointIsClippedBySurfaceOrClipRect(screenSpacePoint, layerImpl))
      return false;
 
   return true;
 }
 }  // namespace cc