Use custom ListContainer to allocate DrawQuads

cc/quads/list_container.cc

 // Copyright 2014 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/quads/list_container.h"
 
 #include <algorithm>
 #include <vector>
 
 #include "cc/base/scoped_ptr_vector.h"
@@ skipping 50 matching lines @@
 
     void* AddElement() {
       DCHECK_LT(size, capacity);
       ++size;
       return LastElement();
     }
 
     char* Begin() const { return data.get(); }
     char* End() const { return data.get() + size * step; }
     char* LastElement() const { return data.get() + (size - 1) * step; }
+    char* ElementAt(size_t index) const { return data.get() + index * step; }
 
    private:
     DISALLOW_COPY_AND_ASSIGN(InnerList);
   };
 
   explicit ListContainerCharAllocator(size_t element_size)
       : element_size_(element_size),
         size_(0),
         list_count_(0),
         last_list_(NULL) {
@@ skipping 285 matching lines @@
   return &*iter;
 }
 
 template <typename BaseElementType>
 const BaseElementType* ListContainer<BaseElementType>::back() const {
   ConstReverseIterator iter = rbegin();
   return &*iter;
 }
 
 template <typename BaseElementType>
+const BaseElementType* ListContainer<BaseElementType>::at(size_t index) const {
+  DCHECK_LT(index, size());
+  size_t list_index;
+  for (list_index = 0; list_index < data_->list_count(); ++list_index) {
+    size_t current_size = data_->InnerListById(list_index)->size;
+    if (index < current_size)
+      break;
+    index -= current_size;
+  }
+  return &*ConstIterator(data_.get(),
+                         list_index,
+                         data_->InnerListById(list_index)->ElementAt(index));
+}
+
+template <typename BaseElementType>
+BaseElementType* ListContainer<BaseElementType>::at(size_t index) {
+  DCHECK_LT(index, size());
+  size_t list_index;
+  for (list_index = 0; list_index < data_->list_count(); ++list_index) {
+    size_t current_size = data_->InnerListById(list_index)->size;
+    if (index < current_size)
+      break;
+    index -= current_size;
+  }
+  return &*Iterator(data_.get(),
+                    list_index,
+                    data_->InnerListById(list_index)->ElementAt(index));
+}
+
+template <typename BaseElementType>
 BaseElementType* ListContainer<BaseElementType>::Allocate(
     size_t size_of_actual_element_in_bytes) {
   DCHECK_LE(size_of_actual_element_in_bytes, data_->element_size());
   void* result = data_->Allocate();
   return static_cast<BaseElementType*>(result);
 }
 
 template <typename BaseElementType>
 size_t ListContainer<BaseElementType>::size() const {
   return data_->size();
@@ skipping 197 matching lines @@
 ListContainer<BaseElementType>::ConstReverseIterator::
 operator++() {
   this->ReverseIncrement();
   return *this;
 }
 
 template class ListContainer<SharedQuadState>;
 template class ListContainer<DrawQuad>;
 
 }  // namespace cc