Use the solid color detection to create solid layers

cc/layers/picture_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 "cc/layers/picture_layer_impl.h"
 
 #include <algorithm>
 #include <limits>
 #include <set>
 
 #include "base/debug/trace_event_argument.h"
 #include "base/time/time.h"
 #include "cc/base/math_util.h"
 #include "cc/base/util.h"
 #include "cc/debug/debug_colors.h"
 #include "cc/debug/micro_benchmark_impl.h"
 #include "cc/debug/traced_value.h"
 #include "cc/layers/append_quads_data.h"
+#include "cc/layers/solid_color_layer_impl.h"
 #include "cc/output/begin_frame_args.h"
 #include "cc/quads/checkerboard_draw_quad.h"
 #include "cc/quads/debug_border_draw_quad.h"
 #include "cc/quads/picture_draw_quad.h"
 #include "cc/quads/solid_color_draw_quad.h"
 #include "cc/quads/tile_draw_quad.h"
 #include "cc/resources/tile_manager.h"
 #include "cc/trees/layer_tree_impl.h"
 #include "cc/trees/occlusion_tracker.h"
 #include "ui/gfx/quad_f.h"
@@ skipping 59 matching lines @@
 
 scoped_ptr<LayerImpl> PictureLayerImpl::CreateLayerImpl(
     LayerTreeImpl* tree_impl) {
   return PictureLayerImpl::Create(tree_impl, id()).PassAs<LayerImpl>();
 }
 
 void PictureLayerImpl::PushPropertiesTo(LayerImpl* base_layer) {
   // It's possible this layer was never drawn or updated (e.g. because it was
   // a descendant of an opacity 0 layer).
   DoPostCommitInitializationIfNeeded();
+
   PictureLayerImpl* layer_impl = static_cast<PictureLayerImpl*>(base_layer);
 
   // We have already synced the important bits from the the active layer, and
   // we will soon swap out its tilings and use them for recycling. However,
   // there are now tiles in this layer's tilings that were unref'd and replaced
   // with new tiles (due to invalidation). This resets all active priorities on
   // the to-be-recycled tiling to ensure replaced tiles don't linger and take
   // memory (due to a stale 'active' priority).
   if (layer_impl->tilings_)
     layer_impl->tilings_->DidBecomeRecycled();
 
   LayerImpl::PushPropertiesTo(base_layer);
 
   // When the pending tree pushes to the active tree, the pending twin
   // becomes recycled.
   layer_impl->twin_layer_ = NULL;
   twin_layer_ = NULL;
 
   layer_impl->pile_ = pile_;
 
+  DCHECK(!pile_->is_solid_color() || !tilings_->num_tilings());

[vmpstr, 2014/09/15 15:45:07]

I like this dcheck, and I think you should put it in more functions both as a
check and as a statement that makes the intentions of what we expect to happen
in a function clear.

[hendrikw, 2014/09/15 16:59:40]

This is the only place in the code that the state of solidness can change, There
is already a DCHECK in CreateTile, and CanHaveTiling returns on it, these are
the most relevant locations.  If you want it in other functions, just let me
know which ones and I'll add it for you.

+
   // Tilings would be expensive to push, so we swap.
   layer_impl->tilings_.swap(tilings_);

[vmpstr, 2014/09/15 15:45:07]

In the case where a non-solid layer becomes solid, I think you have to remove
all tilings from the new recycled tree. We have this notion to ensure that the
recycle tree does not have any unshared tiles, which is important to maintain. 

[danakj, 2014/09/15 16:26:35]

Please add a test for that also.

[hendrikw, 2014/09/15 16:59:40]

We had discussed this a couple of weeks ago, you said doing this would be
expensive since it would force us to recreate tilings that could be reused in
certain situations.  Have you changed your mind on this?

[vmpstr, 2014/09/15 18:30:38]

Yeah, in retrospect, this is important to do right away. In the iterators world
we rely on the fact that we don't have to evict recycle tree tiles since they
can be accessed via some other tree (active). This change without clearing the
tilings would violate that.

   layer_impl->tilings_->SetClient(layer_impl);
   if (tilings_)
     tilings_->SetClient(this);
 
   // Remove invalidated tiles from what will become a recycle tree.
   if (tilings_)
     tilings_->RemoveTilesInRegion(invalidation_);
 
   layer_impl->raster_page_scale_ = raster_page_scale_;
   layer_impl->raster_device_scale_ = raster_device_scale_;
@@ skipping 13 matching lines @@
   // See http://crbug.com/303943
   needs_push_properties_ = true;
 }
 
 void PictureLayerImpl::AppendQuads(
     RenderPass* render_pass,
     const OcclusionTracker<LayerImpl>& occlusion_tracker,
     AppendQuadsData* append_quads_data) {
   DCHECK(!needs_post_commit_initialization_);
 
+  SharedQuadState* shared_quad_state =
+      render_pass->CreateAndAppendSharedQuadState();
+
+  if (pile_->is_solid_color()) {
+    PopulateSharedQuadState(shared_quad_state);
+
+    AppendDebugBorderQuad(
+        render_pass, content_bounds(), shared_quad_state, append_quads_data);
+
+    SolidColorLayerImpl::AppendSolidQuads(
+        render_pass,
+        occlusion_tracker,
+        append_quads_data,
+        shared_quad_state,
+        content_bounds(),
+        draw_properties().target_space_transform,

[vmpstr, 2014/09/15 15:45:07]

Here we pass a target_space_transform, but below we use scaled_draw_transform.
Is this supposed to be consistent? danakj, do you know? :) I'm more curious
because I plan to change this to be Occlusion instead of OcclusionTracker.

[danakj, 2014/09/15 16:26:35]

This is cool. The transform is consistent with the bounds etc that's given to
this function here.

+        pile_->get_solid_color());
+    return;
+  }
+
   float max_contents_scale = MaximumTilingContentsScale();
   gfx::Transform scaled_draw_transform = draw_transform();
   scaled_draw_transform.Scale(SK_MScalar1 / max_contents_scale,
                               SK_MScalar1 / max_contents_scale);
   gfx::Size scaled_content_bounds =
       gfx::ToCeiledSize(gfx::ScaleSize(content_bounds(), max_contents_scale));
 
   gfx::Rect scaled_visible_content_rect =
       gfx::ScaleToEnclosingRect(visible_content_rect(), max_contents_scale);
   scaled_visible_content_rect.Intersect(gfx::Rect(scaled_content_bounds));
 
-  SharedQuadState* shared_quad_state =
-      render_pass->CreateAndAppendSharedQuadState();
   shared_quad_state->SetAll(scaled_draw_transform,
                             scaled_content_bounds,
                             scaled_visible_content_rect,
                             draw_properties().clip_rect,
                             draw_properties().is_clipped,
                             draw_properties().opacity,
                             blend_mode(),
                             sorting_context_id_);
 
   if (current_draw_mode_ == DRAW_MODE_RESOURCELESS_SOFTWARE) {
@@ skipping 387 matching lines @@
   // to force tilings to get managed.
   layer_tree_impl()->set_needs_update_draw_properties();
 }
 
 skia::RefPtr<SkPicture> PictureLayerImpl::GetPicture() {
   return pile_->GetFlattenedPicture();
 }
 
 scoped_refptr<Tile> PictureLayerImpl::CreateTile(PictureLayerTiling* tiling,
                                                const gfx::Rect& content_rect) {
+  DCHECK(!pile_->is_solid_color());
   if (!pile_->CanRaster(tiling->contents_scale(), content_rect))
     return scoped_refptr<Tile>();
 
   int flags = 0;
 
   // TODO(vmpstr): Revisit this. For now, enabling analysis means that we get as
   // much savings on memory as we can. However, for some cases like ganesh or
   // small layers, the amount of time we spend analyzing might not justify
   // memory savings that we can get. Note that we don't handle solid color
   // masks, so we shouldn't bother analyzing those.
@@ skipping 705 matching lines @@
   raster_contents_scale_ = 0.f;
   low_res_raster_contents_scale_ = 0.f;
   raster_source_scale_is_fixed_ = false;
 
   // When raster scales aren't valid, don't update tile priorities until
   // this layer has been updated via UpdateDrawProperties.
   should_update_tile_priorities_ = false;
 }
 
 bool PictureLayerImpl::CanHaveTilings() const {
+  if (pile_->is_solid_color())
+    return false;
   if (!DrawsContent())
     return false;
   if (!pile_->HasRecordings())
     return false;
   return true;
 }
 
 bool PictureLayerImpl::CanHaveTilingWithScale(float contents_scale) const {
   if (!CanHaveTilings())
     return false;
@@ skipping 454 matching lines @@
       PictureLayerTilingSet::TilingRange tiling_range = CurrentTilingRange();
       size_t current_tiling_range_offset = current_tiling_ - tiling_range.start;
       return tiling_range.end - 1 - current_tiling_range_offset;
     }
   }
   NOTREACHED();
   return 0;
 }
 
 }  // namespace cc