Add fixed raster scale use counter histograms.

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 <stddef.h>
 #include <stdint.h>
 
 #include <algorithm>
@@ skipping 51 matching lines @@
 PictureLayerImpl::PictureLayerImpl(LayerTreeImpl* tree_impl,
                                    int id,
                                    bool is_mask)
     : LayerImpl(tree_impl, id),
       twin_layer_(nullptr),
       tilings_(CreatePictureLayerTilingSet()),
       ideal_page_scale_(0.f),
       ideal_device_scale_(0.f),
       ideal_source_scale_(0.f),
       ideal_contents_scale_(0.f),
+      last_ideal_source_scale_(0.f),
       raster_page_scale_(0.f),
       raster_device_scale_(0.f),
       raster_source_scale_(0.f),
       raster_contents_scale_(0.f),
       low_res_raster_contents_scale_(0.f),
       raster_source_scale_is_fixed_(false),
       was_screen_space_transform_animating_(false),
       only_used_low_res_last_append_quads_(false),
       is_mask_(is_mask),
       nearest_neighbor_(false) {
@@ skipping 344 matching lines @@
   if (layer_tree_impl()->IsActiveTree())
     CleanUpTilingsOnActiveLayer(last_append_quads_tilings_);
 
   UpdateIdealScales();
 
   if (!raster_contents_scale_ || ShouldAdjustRasterScale()) {
     RecalculateRasterScales();
     AddTilingsForRasterScale();
   }
 
+  // Inform layer tree impl if we will have blurry content because of fixed
+  // raster scale (note that this check should happen after we
+  // ReclaculateRasterScales, since that's the function that will determine
+  // whether our raster scale is fixed.
+  if (raster_source_scale_is_fixed_ && !has_will_change_transform_hint()) {
+    if (std::abs(raster_source_scale_ - ideal_source_scale_) >=
+        std::numeric_limits<float>::epsilon()) {

[danakj, 2016/05/13 20:41:47]

Why?

[vmpstr, 2016/05/13 21:17:10]

Acknowledged.

+      layer_tree_impl()->SetFixedRasterScaleHasBlurryContent();
+    }
+    if (std::abs(ideal_source_scale_ - last_ideal_source_scale_) >=
+        std::numeric_limits<float>::epsilon()) {
+      layer_tree_impl()->SetFixedRasterScaleAttemptedToChangeScale();
+    }
+  }
+
   if (layer_tree_impl()->IsActiveTree())
     AddLowResolutionTilingIfNeeded();
 
   DCHECK(raster_page_scale_);
   DCHECK(raster_device_scale_);
   DCHECK(raster_source_scale_);
   DCHECK(raster_contents_scale_);
   DCHECK(low_res_raster_contents_scale_);
 
   was_screen_space_transform_animating_ =
@@ skipping 753 matching lines @@
   DCHECK(CanHaveTilings());
 
   float min_contents_scale = MinimumContentsScale();
   DCHECK_GT(min_contents_scale, 0.f);
 
   ideal_page_scale_ = IsAffectedByPageScale()
                           ? layer_tree_impl()->current_page_scale_factor()
                           : 1.f;
   ideal_device_scale_ = layer_tree_impl()->device_scale_factor();
   ideal_contents_scale_ = std::max(GetIdealContentsScale(), min_contents_scale);
+  last_ideal_source_scale_ = ideal_source_scale_;
   ideal_source_scale_ =
       ideal_contents_scale_ / ideal_page_scale_ / ideal_device_scale_;
 }
 
 void PictureLayerImpl::GetDebugBorderProperties(
     SkColor* color,
     float* width) const {
   *color = DebugColors::TiledContentLayerBorderColor();
   *width = DebugColors::TiledContentLayerBorderWidth(layer_tree_impl());
 }
@@ skipping 59 matching lines @@
 bool PictureLayerImpl::IsOnActiveOrPendingTree() const {
   return !layer_tree_impl()->IsRecycleTree();
 }
 
 bool PictureLayerImpl::HasValidTilePriorities() const {
   return IsOnActiveOrPendingTree() &&
          is_drawn_render_surface_layer_list_member();
 }
 
 }  // namespace cc