cc: Don't swap PictureLayerTilingSet on activate.

cc/resources/picture_layer_tiling_set.cc

Index: cc/resources/picture_layer_tiling_set.cc
diff --git a/cc/resources/picture_layer_tiling_set.cc b/cc/resources/picture_layer_tiling_set.cc
index 51896a5b5f7f29cfb287e970fb8b301aaa4b83a0..20a5ff12fc075b0915242f696bc9c32399487a02 100644
--- a/cc/resources/picture_layer_tiling_set.cc
+++ b/cc/resources/picture_layer_tiling_set.cc
@@ -40,15 +40,70 @@ PictureLayerTilingSet::PictureLayerTilingSet(PictureLayerTilingClient* client)
 PictureLayerTilingSet::~PictureLayerTilingSet() {
 }
 
-void PictureLayerTilingSet::SetClient(PictureLayerTilingClient* client) {
-  client_ = client;
-  for (size_t i = 0; i < tilings_.size(); ++i)
-    tilings_[i]->SetClient(client_);
-}
+void PictureLayerTilingSet::UpdateTilingsToCurrentRasterSource(
+    RasterSource* raster_source,
+    const PictureLayerTilingSet* twin_set,
+    const gfx::Size& layer_bounds,
+    const Region& layer_invalidation,
+    float minimum_contents_scale) {
+  RemoveTilingsBelowScale(minimum_contents_scale);
+
+  // Copy over tilings that are shared with the |twin_set| tiling set (if it
+  // exists).
+  if (twin_set) {
+    for (PictureLayerTiling* twin_tiling : twin_set->tilings_) {

[vmpstr, 2014/12/09 00:10:19]

I feel like we could do better in terms of speed.. Like compute all three sets
ahead of time (in both, in twin only, in this only) in one pass, and then
update/create/invalidate in the other pass. I also think this is fine to leave
for later :)

[danakj, 2014/12/09 18:20:23]

Writing something much faster here would be very complicated code in comparison
(like using the knowledge it's sorted by scale and then traversing both this and
other tiling lists kinda like a merge sort.. I'm not convinced it will matter
esp since the FindTilingWithScale is looking at <= 2 (or actually 1 on desktop)
tilings.

+      float contents_scale = twin_tiling->contents_scale();
+      DCHECK_GE(contents_scale, minimum_contents_scale);
+
+      PictureLayerTiling* this_tiling = FindTilingWithScale(contents_scale);
+      if (!this_tiling) {
+        scoped_ptr<PictureLayerTiling> new_tiling =
+            PictureLayerTiling::Create(contents_scale, layer_bounds, client_);
+        tilings_.push_back(new_tiling.Pass());
+        this_tiling = tilings_.back();
+      }
+      this_tiling->CloneTilesAndPropertiesFrom(*twin_tiling);
+    }
+  }
 
-void PictureLayerTilingSet::RemoveTilesInRegion(const Region& region) {
-  for (size_t i = 0; i < tilings_.size(); ++i)
-    tilings_[i]->RemoveTilesInRegion(region);
+  // For unshared tilings, invalidate tiles and update them to the new raster
+  // source.
+  for (PictureLayerTiling* tiling : tilings_) {
+    if (twin_set && twin_set->FindTilingWithScale(tiling->contents_scale()))
+      continue;
+
+    tiling->Resize(layer_bounds);
+    tiling->Invalidate(layer_invalidation);
+    tiling->SetRasterSource(raster_source);
+    // TODO(danakj): Is this needed anymore? Won't they already exist?
+    tiling->CreateMissingTilesInLiveTilesRect();
+
+    // If |twin_set| is present, use the resolutions from there. Otherwise leave
+    // all resolutions as they are.
+    if (twin_set)
+      tiling->set_resolution(NON_IDEAL_RESOLUTION);
+  }
+
+  tilings_.sort(LargestToSmallestScaleFunctor());
+
+#if DCHECK_IS_ON
+  for (PictureLayerTiling* tiling : tilings_) {
+    DCHECK(tiling->tile_size() ==
+           client_->CalculateTileSize(tiling->tiling_size()))
+        << "tile_size: " << tiling->tile_size().ToString()
+        << " tiling_size: " << tiling->tiling_size().ToString()
+        << " CalculateTileSize: "
+        << client_->CalculateTileSize(tiling->tiling_size()).ToString();
+  }
+
+  if (!tilings_.empty()) {
+    size_t num_high_res = std::count_if(tilings_.begin(), tilings_.end(),
+                                        [](PictureLayerTiling* tiling) {
+      return tiling->resolution() == HIGH_RESOLUTION;
+    });
+    DCHECK_EQ(1u, num_high_res);
+  }
+#endif
 }
 
 void PictureLayerTilingSet::CleanUpTilings(
@@ -91,14 +146,6 @@ void PictureLayerTilingSet::CleanUpTilings(
   }
 
   for (auto* tiling : to_remove) {
-    PictureLayerTiling* twin_tiling =
-        twin_set ? twin_set->FindTilingWithScale(tiling->contents_scale())
-                 : nullptr;
-    // Only remove tilings from the twin layer if they have
-    // NON_IDEAL_RESOLUTION.
-    if (twin_tiling && twin_tiling->resolution() == NON_IDEAL_RESOLUTION)
-      twin_set->Remove(twin_tiling);
-
     PictureLayerTiling* recycled_twin_tiling =
         recycled_twin_set
             ? recycled_twin_set->FindTilingWithScale(tiling->contents_scale())
@@ -113,16 +160,24 @@ void PictureLayerTilingSet::CleanUpTilings(
   }
 }
 
+void PictureLayerTilingSet::RemoveNonIdealTilings() {
+  auto to_remove = tilings_.remove_if([](PictureLayerTiling* t) -> bool {

[vmpstr, 2014/12/09 00:10:19]

-> bool is optional here? Or are we requiring it?

[danakj, 2014/12/09 18:20:23]

"However, if a lambda has one statement and that statement is a return statement
(and it returns an expression), the compiler can deduce the return type from the
type of that one returned expression. You have multiple statements in your
lambda, so it doesn't deduce the type."

Woa.

+    return t->resolution() == NON_IDEAL_RESOLUTION;
+  });
+  tilings_.erase(to_remove, tilings_.end());
+}
+
 void PictureLayerTilingSet::MarkAllTilingsNonIdeal() {
   for (auto* tiling : tilings_)
     tiling->set_resolution(NON_IDEAL_RESOLUTION);
 }
 
-bool PictureLayerTilingSet::SyncTilings(const PictureLayerTilingSet& other,
-                                        const gfx::Size& new_layer_bounds,
-                                        const Region& layer_invalidation,
-                                        float minimum_contents_scale,
-                                        RasterSource* raster_source) {
+bool PictureLayerTilingSet::SyncTilingsForTesting(
+    const PictureLayerTilingSet& other,
+    const gfx::Size& new_layer_bounds,
+    const Region& layer_invalidation,
+    float minimum_contents_scale,
+    RasterSource* raster_source) {
   if (new_layer_bounds.IsEmpty()) {
     RemoveAllTilings();
     return false;
@@ -151,8 +206,9 @@ bool PictureLayerTilingSet::SyncTilings(const PictureLayerTilingSet& other,
     if (PictureLayerTiling* this_tiling = FindTilingWithScale(contents_scale)) {
       this_tiling->set_resolution(other.tilings_[i]->resolution());
 
-      this_tiling->UpdateTilesToCurrentRasterSource(
-          raster_source, layer_invalidation, new_layer_bounds);
+      this_tiling->Resize(new_layer_bounds);
+      this_tiling->Invalidate(layer_invalidation);
+      this_tiling->SetRasterSource(raster_source);
       this_tiling->CreateMissingTilesInLiveTilesRect();
       if (this_tiling->resolution() == HIGH_RESOLUTION)
         have_high_res_tiling = true;
@@ -222,6 +278,14 @@ PictureLayerTiling* PictureLayerTilingSet::FindTilingWithResolution(
   return *iter;
 }
 
+void PictureLayerTilingSet::RemoveTilingsBelowScale(float minimum_scale) {
+  auto to_remove =
+      tilings_.remove_if([minimum_scale](PictureLayerTiling* tiling) -> bool {
+        return tiling->contents_scale() < minimum_scale;
+      });
+  tilings_.erase(to_remove, tilings_.end());
+}
+
 void PictureLayerTilingSet::RemoveAllTilings() {
   tilings_.clear();
 }