cc: Add command line switch to control resource usage for impl-side painting.

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 904 matching lines @@
     resource_pool_->resource_provider()->ReleasePixelBuffer(resource->id());
     resource_pool_->ReleaseResource(resource.Pass());
     managed_tile_state.drawing_info.resource_is_being_initialized_ = false;
     DidTileRasterStateChange(tile, IDLE_STATE);
   }
 }
 
 void TileManager::DidFinishTileInitialization(Tile* tile) {
   ManagedTileState& managed_state = tile->managed_state();
   managed_state.drawing_info.resource_is_being_initialized_ = false;
+
   if (tile->priority(ACTIVE_TREE).distance_to_visible_in_pixels == 0)
     client_->DidInitializeVisibleTile();
+
+  // Reduce memory usage when no work is pending.
+  if (!HasPendingWorkScheduled(PENDING_TREE) &&
+      !HasPendingWorkScheduled(ACTIVE_TREE))
+    resource_pool_->ReduceMemoryUsage();
 }
 
 void TileManager::DidTileRasterStateChange(Tile* tile, TileRasterState state) {
   ManagedTileState& mts = tile->managed_state();
   DCHECK_LT(state, NUM_STATES);
 
   for (int i = 0; i < NUM_TREES; ++i) {
     // Decrement count for current state.
     --raster_state_count_[mts.raster_state][i][mts.tree_bin[i]];
     DCHECK_GE(raster_state_count_[mts.raster_state][i][mts.tree_bin[i]], 0);
@@ skipping 153 matching lines @@
     skia::LazyPixelRef* pixel_ref,
     RenderingStatsInstrumentation* stats_instrumentation) {
   TRACE_EVENT0("cc", "TileManager::RunImageDecodeTask");
   base::TimeTicks start_time = stats_instrumentation->StartRecording();
   pixel_ref->Decode();
   base::TimeDelta duration = stats_instrumentation->EndRecording(start_time);
   stats_instrumentation->AddDeferredImageDecode(duration);
 }
 
 }  // namespace cc