cc: Add support for partial swaps when using 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 <limits>
 
 #include "base/basictypes.h"
@@ skipping 1176 matching lines @@
 }
 
 void LayerTreeHostImpl::DidModifyTilePriorities() {
   DCHECK(settings_.impl_side_painting);
   // Mark priorities as dirty and schedule a ManageTiles().
   tile_priorities_dirty_ = true;
   client_->SetNeedsManageTilesOnImplThread();
 }
 
 void LayerTreeHostImpl::DidInitializeVisibleTile() {
-  // TODO(reveman): Determine tiles that changed and only damage
-  // what's necessary.
-  SetFullRootLayerDamage();
   if (client_ && !client_->IsInsideDraw())
     client_->DidInitializeVisibleTileOnImplThread();
 }
 
 void LayerTreeHostImpl::NotifyReadyToActivate() {
   client_->NotifyReadyToActivate();
 }
 
+void LayerTreeHostImpl::NotifyInitializedTiles(Tile* tile) {
+  LayerImpl* layer_impl = NULL;

[reveman, 2014/04/14 20:03:07]

nit: move to where it's first used instead

[sohanjg, 2014/04/15 10:03:48]

Done.

+  if (active_tree_) {

[reveman, 2014/04/14 20:03:07]

nit: maybe cleaner to early out instead of having nested if statements

[sohanjg, 2014/04/15 10:03:48]

Done.

+    layer_impl = active_tree_->FindActiveTreeLayerById(tile->layer_id());
+    if (layer_impl)
+      layer_impl->UnionDamageRect(tile->content_rect());

[danakj, 2014/04/14 17:17:07]

The tile's content rect is in the tiling's content space, which is not the same
thing as the layer's content space. If you scale it by the tile's tiling's
content scale, you'll get back to layer space.

So something like tile->content_rect() * / tiling_content_scale_{x,y} would give
you a rect in the layer's content space. You probably want this rect as floats,
like update_rect_ since each pixel there may be many physical pixels.

[sohanjg, 2014/04/15 10:03:48]

Done.

+  }
+}
+
 void LayerTreeHostImpl::SetMemoryPolicy(const ManagedMemoryPolicy& policy) {
   SetManagedMemoryPolicy(policy, zero_budget_);
 }
 
 void LayerTreeHostImpl::SetTreeActivationCallback(
     const base::Closure& callback) {
   DCHECK(proxy_->IsImplThread());
   DCHECK(settings_.impl_side_painting || callback.is_null());
   tree_activation_callback_ = callback;
 }
@@ skipping 1812 matching lines @@
   swap_promise_monitor_.erase(monitor);
 }
 
 void LayerTreeHostImpl::NotifySwapPromiseMonitorsOfSetNeedsRedraw() {
   std::set<SwapPromiseMonitor*>::iterator it = swap_promise_monitor_.begin();
   for (; it != swap_promise_monitor_.end(); it++)
     (*it)->OnSetNeedsRedrawOnImpl();
 }
 
 }  // namespace cc