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

Source/core/html/canvas/WebGLRenderingContextBase.h

 /*
  * Copyright (C) 2009 Apple 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:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 82 matching lines @@
 class WebGLUniformLocation;
 class WebGLVertexArrayObjectOES;
 
 class WebGLRenderingContextLostCallback;
 class WebGLRenderingContextErrorMessageCallback;
 
 class WebGLRenderingContextBase: public CanvasRenderingContext, public ActiveDOMObject, private Page::MultisamplingChangedObserver {
 public:
     virtual ~WebGLRenderingContextBase();
 
-    virtual bool is3d() const OVERRIDE { return true; }
-    virtual bool isAccelerated() const OVERRIDE { return true; }
     virtual unsigned version() const = 0;
     virtual String contextName() const = 0;
     virtual void registerContextExtensions() = 0;
 
     static unsigned getWebGLVersion(const CanvasRenderingContext*);
 
     int drawingBufferWidth() const;
     int drawingBufferHeight() const;
 
     void activeTexture(GLenum texture);
@@ skipping 206 matching lines @@
 
         // A synthetic lost context that should attempt to recover automatically
         AutoRecoverSyntheticLostContext
     };
     void forceLostContext(LostContextMode);
     void forceRestoreContext();
     void loseContextImpl(LostContextMode);
 
     blink::WebGraphicsContext3D* webContext() const { return m_drawingBuffer->context(); }
     WebGLContextGroup* contextGroup() const { return m_contextGroup.get(); }
-    virtual blink::WebLayer* platformLayer() const OVERRIDE;
     Extensions3DUtil* extensionsUtil();
 
     void reshape(int width, int height);
 
     void markLayerComposited();
-    virtual void paintRenderingResultsToCanvas() OVERRIDE;
     PassRefPtrWillBeRawPtr<ImageData> paintRenderingResultsToImageData();
 
     void removeSharedObject(WebGLSharedObject*);
     void removeContextObject(WebGLContextObject*);
 
     unsigned maxVertexAttribs() const { return m_maxVertexAttribs; }
 
     // ActiveDOMObject notifications
     virtual bool hasPendingActivity() const OVERRIDE;
     virtual void stop() OVERRIDE;
 
 protected:
     friend class WebGLDrawBuffers;
     friend class WebGLFramebuffer;
     friend class WebGLObject;
     friend class OESVertexArrayObject;
     friend class WebGLDebugShaders;
     friend class WebGLCompressedTextureATC;
     friend class WebGLCompressedTextureETC1;
     friend class WebGLCompressedTexturePVRTC;
     friend class WebGLCompressedTextureS3TC;
     friend class WebGLRenderingContextErrorMessageCallback;
     friend class WebGLVertexArrayObjectOES;
     friend class ScopedTexture2DRestorer;
 
     WebGLRenderingContextBase(HTMLCanvasElement*, PassOwnPtr<blink::WebGraphicsContext3D>, WebGLContextAttributes*);
     void initializeNewContext();
     void setupFlags();
 
+    // CanvasRenderingContext implementation.
+    virtual bool is3d() const OVERRIDE { return true; }

[Justin Novosad, 2014/04/28 15:21:42]

These are public in the base class. Making the protected here is confusing.

[Ken Russell (switch to Gerrit), 2014/04/28 20:51:45]

Actually, it was a common pattern in WebKit, anyway, to make the implementations
of base class methods private. This movement seems OK to me. I think they could
actually be made private instead of protected.

[dshwang, 2014/04/29 16:07:04]

I wanted to put them in private:, but there is not "private:" in this class.

+    virtual bool isAccelerated() const OVERRIDE { return true; }
+    virtual void setIsHidden(bool) OVERRIDE;
+    virtual void paintRenderingResultsToCanvas() OVERRIDE;
+    virtual blink::WebLayer* platformLayer() const OVERRIDE;
+
     void addSharedObject(WebGLSharedObject*);
     void addContextObject(WebGLContextObject*);
     void detachAndRemoveAllObjects();
 
     void destroyContext();
     void markContextChanged(ContentChangeType);
 
     // Query if the GL implementation is NPOT strict.
     bool isGLES2NPOTStrict() { return m_isGLES2NPOTStrict; }
     // Query if depth_stencil buffer is supported.
@@ skipping 539 matching lines @@
     // If the vector is empty, return the maximum allowed active context number.
     static size_t oldestContextIndex();
     static IntSize oldestContextSize();
 };
 
 DEFINE_TYPE_CASTS(WebGLRenderingContextBase, CanvasRenderingContext, context, context->is3d(), context.is3d());
 
 } // namespace WebCore
 
 #endif // WebGLRenderingContextBase_h