Implement on demand quad rasterization for PicturePiles.

cc/resources/tile_manager.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/resources/tile_manager.h"
 
 #include <algorithm>
 
 #include "base/bind.h"
 #include "base/debug/trace_event.h"
@@ skipping 578 matching lines @@
 
   size_t bytes_allocatable =
       global_state_.memory_limit_in_bytes - unreleasable_bytes;
   size_t bytes_that_exceeded_memory_budget_in_now_bin = 0;
   size_t bytes_left = bytes_allocatable;
   for (TileVector::iterator it = live_or_allocated_tiles_.begin();
        it != live_or_allocated_tiles_.end();
        ++it) {
     Tile* tile = *it;
     ManagedTileState& mts = tile->managed_state();
     if (!tile->drawing_info().requires_resource())

[nduca, 2013/03/21 02:22:48]

@vmpstr: why do we sometimes say tile->drawing info and sometimes mts->drawing
info? makes no sense to my addled brain

[vmpstr, 2013/03/21 16:34:11]

Yeah that should be fixed. I prefer using tile->drawing_info(), but sometimes
using mts is just a lot less typing... I opened crbug.com/222761 to fix this

       continue;
 
     size_t tile_bytes = tile->bytes_consumed_if_allocated();
     if (!mts.drawing_info.can_be_freed_)
       continue;
     if (mts.bin[HIGH_PRIORITY_BIN] == NEVER_BIN &&
         mts.bin[LOW_PRIORITY_BIN] == NEVER_BIN) {
       mts.can_use_gpu_memory = false;
       FreeResourcesForTile(tile);
       continue;
     }
     if (tile_bytes > bytes_left) {
       mts.can_use_gpu_memory = false;
       if (mts.bin[HIGH_PRIORITY_BIN] == NOW_BIN ||
           mts.bin[LOW_PRIORITY_BIN] == NOW_BIN)
           bytes_that_exceeded_memory_budget_in_now_bin += tile_bytes;
       FreeResourcesForTile(tile);

[nduca, 2013/03/21 02:22:48]

so um, where is the part of this loop that says "please use texgture mode?" I
dont see it... what happens if a tile gets rasterize on demand one fram, but
gets to line 620 on the next frame?

[Leandro Graciá Gil, 2013/03/21 03:35:50]

I don't see any specific consequences of that. If it gets to line 620 it will
work as it currently does. What do you exactly mean?

[vmpstr, 2013/03/21 16:34:11]

If tile->drawing_info().mode() is set to PICTURE_PILE_MODE, then it would not be
unset anywhere: this means that we will always rasterize on demand. I think
after this if-block we want to set the mode to TEXTURE_MODE

[Leandro Graciá Gil, 2013/03/21 16:42:48]

I see your point. Fixed.

+      tile->drawing_info().set_rasterize_on_demand();
       continue;
     }
     bytes_left -= tile_bytes;
     mts.can_use_gpu_memory = true;
     if (!mts.drawing_info.resource_ &&
         !mts.drawing_info.resource_is_being_initialized_) {
       tiles_that_need_to_be_rasterized_.push_back(tile);
       DidTileRasterStateChange(tile, WAITING_FOR_RASTER_STATE);
     }
   }
@@ skipping 488 matching lines @@
     decode_begin_time = base::TimeTicks::HighResNow();
   pixel_ref->Decode();
   if (stats) {
     stats->totalDeferredImageDecodeCount++;
     stats->totalDeferredImageDecodeTime +=
         base::TimeTicks::HighResNow() - decode_begin_time;
   }
 }
 
 }  // namespace cc