Find cached display items directly during painting

third_party/WebKit/Source/platform/graphics/ContiguousContainer.h

 // Copyright 2015 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.
 
 #ifndef ContiguousContainer_h
 #define ContiguousContainer_h
 
 #include "platform/PlatformExport.h"
 #include "wtf/Alignment.h"
 #include "wtf/Allocator.h"
@@ skipping 41 matching lines @@
     size_t capacityInBytes() const;
     size_t usedCapacityInBytes() const;
     size_t memoryUsageInBytes() const;
 
     // These do not invoke constructors or destructors.
     void reserveInitialCapacity(size_t, const char* typeName);
     void* allocate(size_t objectSize, const char* typeName);
     void removeLast();
     void clear();
     void swap(ContiguousContainerBase&);
+    void removeEmptyBuffers();

[jbroman, 2016/07/06 19:09:37]

Mind a comment clarifying the intended use of this? I'm a little worried it will
imply that we otherwise never discard buffers. Something like:

// Discards excess buffer capacity. Intended for use when no more appending is
anticipated.

[Xianzhu, 2016/07/06 19:29:34]

Done.

 
     Vector<void*> m_elements;
 
 private:
     class Buffer;
 
     Buffer* allocateNewBufferForNextAllocation(size_t, const char* typeName);
 
     Vector<std::unique_ptr<Buffer>> m_buffers;
     unsigned m_endIndex;
@@ skipping 63 matching lines @@
 
         ContiguousContainerBase::operator=(std::move(source));
         return *this;
     }
 
     using ContiguousContainerBase::size;
     using ContiguousContainerBase::isEmpty;
     using ContiguousContainerBase::capacityInBytes;
     using ContiguousContainerBase::usedCapacityInBytes;
     using ContiguousContainerBase::memoryUsageInBytes;
+    using ContiguousContainerBase::removeEmptyBuffers;
 
     iterator begin() { return iterator(m_elements.begin()); }
     iterator end() { return iterator(m_elements.end()); }
     const_iterator begin() const { return const_iterator(m_elements.begin()); }
     const_iterator end() const { return const_iterator(m_elements.end()); }
     reverse_iterator rbegin() { return reverse_iterator(m_elements.rbegin()); }
     reverse_iterator rend() { return reverse_iterator(m_elements.rend()); }
     const_reverse_iterator rbegin() const { return const_reverse_iterator(m_elements.rbegin()); }
     const_reverse_iterator rend() const { return const_reverse_iterator(m_elements.rend()); }
 
@@ skipping 56 matching lines @@
         ASSERT(alignedSize % alignment == 0);
         ASSERT(alignedSize >= size);
         ASSERT(alignedSize < size + alignment);
         return alignedSize;
     }
 };
 
 } // namespace blink
 
 #endif // ContiguousContainer_h