WebGL: Free temporary GPU resources held by inactive or hidden WebGL.

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 111 matching lines @@
     // texture.
     void setActiveTextureUnit(GLint textureUnit) { m_activeTextureUnit = textureUnit; }
 
     bool multisample() const;
 
     Platform3DObject framebuffer() const;
 
     void markContentsChanged();
     void markLayerComposited();
     bool layerComposited() const;
+    void setIsHidden(bool);
 
     blink::WebLayer* platformLayer();
     void paintCompositedResultsToCanvas(ImageBuffer*);
 
     blink::WebGraphicsContext3D* context();
 
     // WebExternalTextureLayerClient implementation.
     virtual bool prepareMailbox(blink::WebExternalTextureMailbox*, blink::WebExternalBitmap*) OVERRIDE;
     virtual void mailboxReleased(const blink::WebExternalTextureMailbox&) OVERRIDE;
 
     // Destroys the TEXTURE_2D binding for the owned context
     bool copyToPlatformTexture(blink::WebGraphicsContext3D*, Platform3DObject texture, GLenum internalFormat,
         GLenum destType, GLint level, bool premultiplyAlpha, bool flipY);
 
     void setPackAlignment(GLint param);
 
     void paintRenderingResultsToCanvas(ImageBuffer*);
     PassRefPtr<Uint8ClampedArray> paintRenderingResultsToImageData(int&, int&);
 
 protected: // For unittests
     DrawingBuffer(
         PassOwnPtr<blink::WebGraphicsContext3D>,
         PassOwnPtr<Extensions3DUtil>,
         bool multisampleExtensionSupported,
         bool packedDepthStencilExtensionSupported, PreserveDrawingBuffer, PassRefPtr<ContextEvictionManager>);
 
     bool initialize(const IntSize&);
 
 private:
-    void mailboxReleasedWhileDestructionInProgress(const blink::WebExternalTextureMailbox&);
+    void mailboxReleasedWithoutRecycling(const blink::WebExternalTextureMailbox&);
 
     unsigned createColorTexture(const IntSize& size = IntSize());
     // 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();
 
     PassRefPtr<MailboxInfo> recycledMailbox();
     PassRefPtr<MailboxInfo> createNewMailbox(unsigned);
     void deleteMailbox(const blink::WebExternalTextureMailbox&);
+    void freeRecycledMailboxes();
 
     // 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.
     static int pixelDelta(const IntSize& newSize, const IntSize& curSize);
 
     // 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);
@@ skipping 60 matching lines @@
     MultisampleMode m_multisampleMode;
 
     blink::WebGraphicsContext3D::Attributes m_attributes;
     unsigned m_internalColorFormat;
     unsigned m_colorFormat;
     unsigned m_internalRenderbufferFormat;
     int m_maxTextureSize;
     int m_sampleCount;
     int m_packAlignment;
     bool m_destructionInProgress;
+    bool m_isHidden;
 
     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;
 
     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