Enable WebGL rendering into ImageCHROMIUM, backed by a scanout buffer to enable overlay suppor…

Source/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 142 matching lines @@
         PassOwnPtr<blink::WebGraphicsContext3D>,
         PassOwnPtr<Extensions3DUtil>,
         bool multisampleExtensionSupported,
         bool packedDepthStencilExtensionSupported, PreserveDrawingBuffer, PassRefPtr<ContextEvictionManager>);
 
     bool initialize(const IntSize&);
 
 private:
     void mailboxReleasedWhileDestructionInProgress(const blink::WebExternalTextureMailbox&);
 
-    unsigned createColorTexture(const IntSize& size = IntSize());
+    unsigned createColorTexture();
     // Create the depth/stencil and multisample buffers, if needed.
     void createSecondaryBuffers();
     bool resizeFramebuffer(const IntSize&);
     bool resizeMultisampleFramebuffer(const IntSize&);
     void resizeDepthStencil(const IntSize&);
 
     // Bind to the m_framebufferBinding if it's not 0.
     void restoreFramebufferBinding();
 
     void clearPlatformLayer();
@@ skipping 23 matching lines @@
     // Helper function which does a readback from the currently-bound
     // framebuffer into a buffer of a certain size with 4-byte pixels.
     void readBackFramebuffer(unsigned char* pixels, int width, int height, ReadbackOrder, WebGLImageConversion::AlphaOp);
 
     // Helper function to flip a bitmap vertically.
     void flipVertically(uint8_t* data, int width, int height);
 
     // Helper to texImage2D with pixel==0 case: pixels are initialized to 0.
     // By default, alignment is 4, the OpenGL default setting.
     void texImage2DResourceSafe(GLenum target, GLint level, GLenum internalformat, GLsizei width, GLsizei height, GLint border, GLenum format, GLenum type, GLint alignment = 4);
+    // Allocate buffer storage to be sent to compositor using either texImage2D or CHROMIUM_image based on available support.
+    void allocateTextureMemory(Platform3DObject textureId, const IntSize&);
+    void deleteChromiumImageForTexture(Platform3DObject textureId);
 
     PreserveDrawingBuffer m_preserveDrawingBuffer;
     bool m_scissorEnabled;
     Platform3DObject m_texture2DBinding;
     Platform3DObject m_framebufferBinding;
     GLenum m_activeTextureUnit;
 
     OwnPtr<blink::WebGraphicsContext3D> m_context;
     OwnPtr<Extensions3DUtil> m_extensionsUtil;
     IntSize m_size;
@@ skipping 38 matching lines @@
     int m_sampleCount;
     int m_packAlignment;
     bool m_destructionInProgress;
 
     OwnPtr<blink::WebExternalTextureLayer> m_layer;
 
     // All of the mailboxes that this DrawingBuffer has ever created.
     Vector<RefPtr<MailboxInfo> > m_textureMailboxes;
     // Mailboxes that were released by the compositor can be used again by this DrawingBuffer.
     Deque<blink::WebExternalTextureMailbox> m_recycledMailboxQueue;
+    // If we used CHROMIUM_image as the backing storage for our buffers,
+    // we need to know the mapping from texture id to image.
+    HashMap<Platform3DObject, blink::WGC3Duint> m_textureToImageChromiumMap;
 
     RefPtr<ContextEvictionManager> m_contextEvictionManager;
 
     // If the width and height of the Canvas's backing store don't
     // match those that we were given in the most recent call to
     // reshape(), then we need an intermediate bitmap to read back the
     // frame buffer into. This seems to happen when CSS styles are
     // used to resize the Canvas.
     SkBitmap m_resizingBitmap;
 
     // Used to flip a bitmap vertically.
     Vector<uint8_t> m_scanline;
 };
 
 } // namespace WebCore
 
 #endif // DrawingBuffer_h