Raster PictureLayerTiling with fractional translation

cc/tiles/tile_manager.cc

Index: cc/tiles/tile_manager.cc
diff --git a/cc/tiles/tile_manager.cc b/cc/tiles/tile_manager.cc
index 7323c21752edb0ffdae505ddb78c9174d434e8fe..e5edf10627ba14a1a704a91282eab40ab5918643 100644
--- a/cc/tiles/tile_manager.cc
+++ b/cc/tiles/tile_manager.cc
@@ -63,6 +63,7 @@ class RasterTaskImpl : public TileTask {
         content_rect_(tile->content_rect()),
         invalid_content_rect_(invalidated_rect),
         contents_scale_(tile->contents_scale()),
+        contents_translation_(tile->contents_translation()),
         playback_settings_(playback_settings),
         tile_resolution_(tile_resolution),
         layer_id_(tile->layer_id()),
@@ -91,7 +92,8 @@ class RasterTaskImpl : public TileTask {
 
     raster_buffer_->Playback(raster_source_.get(), content_rect_,
                              invalid_content_rect_, new_content_id_,
-                             contents_scale_, playback_settings_);
+                             contents_scale_, contents_translation_,
+                             playback_settings_);
   }
 
   // Overridden from TileTask:
@@ -126,6 +128,7 @@ class RasterTaskImpl : public TileTask {
   gfx::Rect content_rect_;
   gfx::Rect invalid_content_rect_;
   float contents_scale_;
+  gfx::Vector2dF contents_translation_;
   RasterSource::PlaybackSettings playback_settings_;
   TileResolution tile_resolution_;
   int layer_id_;
@@ -641,9 +644,12 @@ TileManager::PrioritizedWorkToSchedule TileManager::AssignGpuMemoryToTiles() {
       // TODO(sohanjg): Check if we could use a shared analysis
       // canvas which is reset between tiles.
       SkColor color = SK_ColorTRANSPARENT;
+      gfx::RectF layer_rect(tile->content_rect());
+      layer_rect.Offset(-tile->contents_translation());
+      layer_rect.Scale(1 / tile->contents_scale());
       bool is_solid_color =
           prioritized_tile.raster_source()->PerformSolidColorAnalysis(
-              tile->content_rect(), tile->contents_scale(), &color);
+              gfx::ToEnclosingRect(layer_rect), 1.f, &color);

[enne (OOO), 2016/07/26 00:22:16]

You should probably pass the translation through here.

[trchen, 2016/08/03 06:06:07]

IMO it is better to avoid RasterSource from knowing tiling details like contents
space. Either way is doable. What's the advantage of letting RasterSource handle
it?

       if (is_solid_color) {
         tile->draw_info().set_solid_color(color);
         tile->draw_info().set_was_ever_ready_to_draw();