Limit the number of WebGL contexts that are active at any given time

Source/core/platform/graphics/gpu/DrawingBuffer.h

 /*
  * Copyright (c) 2010, Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 134 matching lines @@
 
     PassRefPtr<MailboxInfo> getRecycledMailbox();
     PassRefPtr<MailboxInfo> createNewMailbox(unsigned);
 
     // Updates the current size of the buffer, ensuring that s_currentResourceUsePixels is updated.
     void setSize(const IntSize& size);
 
     // Calculates the difference in pixels between the current buffer size and the proposed size.
     int pixelDelta(const IntSize& size);
 
+    // Given the desired buffer size, provides the largest dimensions that will fit in the pixel budget
+    // Returns true if the buffer will only fit if the oldest WebGL context is forcibly lost
+    IntSize adjustSizeWithContextEviction(const IntSize&, bool& evictContext);
+
     PreserveDrawingBuffer m_preserveDrawingBuffer;
     bool m_scissorEnabled;
     Platform3DObject m_texture2DBinding;
     Platform3DObject m_framebufferBinding;
     GC3Denum m_activeTextureUnit;
 
     RefPtr<GraphicsContext3D> m_context;
     IntSize m_size;
     bool m_multisampleExtensionSupported;
     bool m_packedDepthStencilExtensionSupported;
@@ skipping 25 matching lines @@
     // All of the mailboxes that this DrawingBuffer has ever created.
     Vector<RefPtr<MailboxInfo> > m_textureMailboxes;
     // Mailboxes that were released by the compositor and can be used again by this DrawingBuffer.
     Vector<RefPtr<MailboxInfo> > m_recycledMailboxes;
     RefPtr<MailboxInfo> m_lastColorBuffer;
 };
 
 } // namespace WebCore
 
 #endif // DrawingBuffer_h