Revert of Use element id's for animations

third_party/WebKit/Source/platform/graphics/CompositorMutableStateProvider.cpp

 // Copyright 2016 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 "platform/graphics/CompositorMutableStateProvider.h"
 
 #include "cc/layers/layer_impl.h"
 #include "cc/trees/layer_tree_impl.h"
-#include "platform/graphics/CompositorElementId.h"
-#include "platform/graphics/CompositorMutableProperties.h"
 #include "platform/graphics/CompositorMutableState.h"
 #include "platform/graphics/CompositorMutation.h"
 #include "wtf/PassOwnPtr.h"
 
 namespace blink {
 
 CompositorMutableStateProvider::CompositorMutableStateProvider(cc::LayerTreeImpl* state, CompositorMutations* mutations)
     : m_state(state)
     , m_mutations(mutations)
 {
 }
 
 CompositorMutableStateProvider::~CompositorMutableStateProvider() {}
 
 PassOwnPtr<CompositorMutableState>
 CompositorMutableStateProvider::getMutableStateFor(uint64_t element_id)
 {
-    cc::LayerImpl* mainLayer = m_state->LayerByElementId(createCompositorElementId(element_id, CompositorSubElementId::Primary));
-    cc::LayerImpl* scrollLayer = m_state->LayerByElementId(createCompositorElementId(element_id, CompositorSubElementId::Scroll));
+    cc::LayerTreeImpl::ElementLayers layers = m_state->GetMutableLayers(element_id);
 
-    if (!mainLayer && !scrollLayer)
+    if (!layers.main && !layers.scroll)
         return nullptr;
 
     // Ensure that we have an entry in the map for |element_id| but do as few
     // allocations and queries as possible. This will update the map only if we
     // have not added a value for |element_id|.
     auto result = m_mutations->map.add(element_id, nullptr);
 
     // Only if this is a new entry do we want to allocate a new mutation.
     if (result.isNewEntry)
         result.storedValue->value = adoptPtr(new CompositorMutation);
 
-    return adoptPtr(new CompositorMutableState(result.storedValue->value.get(), mainLayer, scrollLayer));
+    return adoptPtr(new CompositorMutableState(result.storedValue->value.get(), layers.main, layers.scroll));
 }
 
 } // namespace blink