cc: Low quality support for low res tiles

cc/resources/tile_manager.cc

Index: cc/resources/tile_manager.cc
diff --git a/cc/resources/tile_manager.cc b/cc/resources/tile_manager.cc
index f965981ffaa16ef8cec1b58136c2ea1c11412cdf..e6350f29f2da64feedc3aa0d3a6aefab92e0810f 100644
--- a/cc/resources/tile_manager.cc
+++ b/cc/resources/tile_manager.cc
@@ -16,6 +16,7 @@
 #include "cc/resources/image_raster_worker_pool.h"
 #include "cc/resources/pixel_buffer_raster_worker_pool.h"
 #include "cc/resources/tile.h"
+#include "skia/ext/paint_simplifier.h"
 #include "third_party/skia/include/core/SkCanvas.h"
 #include "ui/gfx/rect_conversions.h"
 
@@ -23,6 +24,18 @@ namespace cc {
 
 namespace {
 
+class DisableLCDTextFilter : public SkDrawFilter {
+ public:
+  // SkDrawFilter interface.
+  virtual bool filter(SkPaint* paint, SkDrawFilter::Type type) OVERRIDE {
+    if (type != SkDrawFilter::kText_Type)
+      return true;
+
+    paint->setLCDRenderText(false);
+    return true;
+  }
+};
+
 // Determine bin based on three categories of tiles: things we need now,
 // things we need soon, and eventually.
 inline TileManagerBin BinFromTilePriority(const TilePriority& prio) {
@@ -393,6 +406,19 @@ void TileManager::AddRequiredTileForActivation(Tile* tile) {
   tiles_that_need_to_be_initialized_for_activation_.insert(tile);
 }
 
+unsigned TileManager::DetermineRasterFlags(const Tile* tile) const {
+  DCHECK(tile);
+  DCHECK(tile->picture_pile());
+
+  unsigned raster_flags = 0;
+  if (tile->picture_pile()->can_use_lcd_text())
+    raster_flags |= USE_LCD_TEXT;
+
+  if (tile->managed_state().resolution != LOW_RESOLUTION)
+    raster_flags |= USE_HIGH_QUALITY;
+  return raster_flags;
+}
+
 void TileManager::AssignGpuMemoryToTiles() {
   TRACE_EVENT0("cc", "TileManager::AssignGpuMemoryToTiles");
 
@@ -446,11 +472,15 @@ void TileManager::AssignGpuMemoryToTiles() {
     if (tile_version.resource_)
       tile_bytes += tile->bytes_consumed_if_allocated();
 
+    unsigned current_raster_flags = tile_version.raster_flags_;
+    unsigned required_raster_flags = DetermineRasterFlags(tile);
+
     // It will cost to allocate a resource.
-    // Note that this is separate from the above condition,
-    // so that it's clear why we're adding memory.
-    if (!tile_version.resource_ && mts.raster_task.is_null())
+    if (mts.raster_task.is_null() &&
+        (!tile_version.resource_ ||
+         (current_raster_flags != required_raster_flags))) {
       tile_bytes += tile->bytes_consumed_if_allocated();
+    }
 
     // Tile is OOM.
     if (tile_bytes > bytes_left) {
@@ -476,8 +506,10 @@ void TileManager::AssignGpuMemoryToTiles() {
     if (higher_priority_tile_oomed)
       continue;
 
-    if (!tile_version.resource_)
+    if (!tile_version.resource_ ||
+        (current_raster_flags != required_raster_flags)) {
       tiles_that_need_to_be_rasterized_.push_back(tile);
+    }
 
     if (!tile_version.resource_ && tile->required_for_activation())
       AddRequiredTileForActivation(tile);
@@ -561,7 +593,8 @@ void TileManager::ScheduleTasks() {
     ManagedTileState& mts = tile->managed_state();
 
     DCHECK(tile->tile_version().requires_resource());
-    DCHECK(!tile->tile_version().resource_);
+    DCHECK(!tile->tile_version().resource_ ||
+           (tile->tile_version().raster_flags_ != DetermineRasterFlags(tile)));
 
     // Create raster task for this tile if necessary.
     if (mts.raster_task.is_null())
@@ -610,6 +643,7 @@ TileManager::RasterTaskMetadata TileManager::GetRasterTaskMetadata(
   metadata.layer_id = tile.layer_id();
   metadata.tile_id = &tile;
   metadata.source_frame_number = tile.source_frame_number();
+  metadata.raster_flags = DetermineRasterFlags(&tile);
   return metadata;
 }
 
@@ -655,6 +689,7 @@ RasterWorkerPool::RasterTask TileManager::CreateRasterTask(Tile* tile) {
     pending_decode_tasks_[id] = decode_task;
   }
 
+  RasterTaskMetadata metadata = GetRasterTaskMetadata(*tile);
   return RasterWorkerPool::RasterTask(
       tile->picture_pile(),
       const_resource,
@@ -664,19 +699,20 @@ RasterWorkerPool::RasterTask TileManager::CreateRasterTask(Tile* tile) {
                             tile->content_rect(),
                             tile->contents_scale(),
                             use_color_estimator_,
-                            GetRasterTaskMetadata(*tile),
+                            metadata,
                             rendering_stats_instrumentation_),
                  base::Bind(&TileManager::RunRasterTask,
                             analysis,
                             tile->content_rect(),
                             tile->contents_scale(),
-                            GetRasterTaskMetadata(*tile),
+                            metadata,
                             rendering_stats_instrumentation_)),
       base::Bind(&TileManager::OnRasterTaskCompleted,
                  base::Unretained(this),
                  make_scoped_refptr(tile),
                  base::Passed(&resource),
-                 base::Owned(analysis)),
+                 base::Owned(analysis),
+                 metadata.raster_flags),
       &decode_tasks);
 }
 
@@ -684,6 +720,7 @@ void TileManager::OnRasterTaskCompleted(
     scoped_refptr<Tile> tile,
     scoped_ptr<ResourcePool::Resource> resource,
     PicturePileImpl::Analysis* analysis,
+    unsigned raster_flags,
     bool was_canceled) {
   TRACE_EVENT1("cc", "TileManager::OnRasterTaskCompleted",
                "was_canceled", was_canceled);
@@ -697,6 +734,12 @@ void TileManager::OnRasterTaskCompleted(
     return;
   }
 
+  if (tile->tile_version().resource_) {
+    resource_pool_->ReleaseResource(tile->tile_version().resource_.Pass());
+    DCHECK(tile->tile_version().raster_flags_ != raster_flags);
+    tile->tile_version().raster_flags_ = 0;
+  }
+
   mts.picture_pile_analysis = *analysis;
   mts.picture_pile_analyzed = true;
 
@@ -705,6 +748,7 @@ void TileManager::OnRasterTaskCompleted(
     resource_pool_->ReleaseResource(resource.Pass());
   } else {
     tile->tile_version().resource_ = resource.Pass();
+    tile->tile_version().raster_flags_ = raster_flags;
   }
 
   DidFinishTileInitialization(tile.get());
@@ -790,6 +834,7 @@ scoped_ptr<base::Value> TileManager::RasterTaskMetadata::AsValue() const {
                   is_tile_in_pending_tree_now_bin);
   res->Set("resolution", TileResolutionAsValue(tile_resolution).release());
   res->SetInteger("source_frame_number", source_frame_number);
+  res->SetInteger("raster_flags", raster_flags);
   return res.PassAs<base::Value>();
 }
 
@@ -817,6 +862,14 @@ bool TileManager::RunRasterTask(
 
   SkCanvas canvas(device);
 
+  skia::RefPtr<SkDrawFilter> draw_filter;
+  if ((metadata.raster_flags & USE_HIGH_QUALITY) == 0)
+    draw_filter = skia::AdoptRef(new skia::PaintSimplifier);
+  else if ((metadata.raster_flags & USE_LCD_TEXT) == 0)
+    draw_filter = skia::AdoptRef(new DisableLCDTextFilter);
+
+  canvas.setDrawFilter(draw_filter.get());
+
   if (stats_instrumentation->record_rendering_stats()) {
     PicturePileImpl::RasterStats raster_stats;
     picture_pile->RasterToBitmap(&canvas, rect, contents_scale, &raster_stats);