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

cc/trees/layer_tree_host_impl.cc

 // Copyright 2011 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/trees/layer_tree_host_impl.h"
 
 #include <algorithm>
 
 #include "base/basictypes.h"
 #include "base/debug/trace_event.h"
@@ skipping 841 matching lines @@
     client_->OnCanDrawStateChanged(CanDraw());
     client_->RenewTreePriority();
   }
   client_->SendManagedMemoryStats();
 
   if (tile_manager_) {
     GlobalStateThatImpactsTilePriority new_state(tile_manager_->GlobalState());
     new_state.memory_limit_in_bytes = visible_ ?
                                       policy.bytes_limit_when_visible :
                                       policy.bytes_limit_when_not_visible;
+    // TODO(reveman): We should avoid keeping around unused resources if
+    // possible. crbug.com/224475
+    new_state.unused_memory_limit_in_bytes =
+        (new_state.memory_limit_in_bytes *
+         settings_.max_unused_resource_memory_percentage) / 100;
     new_state.memory_limit_policy =
         ManagedMemoryPolicy::PriorityCutoffToTileMemoryLimitPolicy(
             visible_ ?
             policy.priority_cutoff_when_visible :
             policy.priority_cutoff_when_not_visible);
     tile_manager_->SetGlobalState(new_state);
   }
 }
 
 bool LayerTreeHostImpl::HasImplThread() const {
@@ skipping 1165 matching lines @@
 }
 
 void LayerTreeHostImpl::SetDebugState(const LayerTreeDebugState& debug_state) {
   if (debug_state_.continuous_painting != debug_state.continuous_painting)
     paint_time_counter_->ClearHistory();
 
   debug_state_ = debug_state;
 }
 
 }  // namespace cc