Defer WebGL lost context restore until visible.

third_party/WebKit/Source/modules/webgl/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 350 matching lines @@
     void viewport(GLint x, GLint y, GLsizei width, GLsizei height);
 
     // WEBGL_lose_context support
     enum AutoRecoveryMethod {
         // Don't restore automatically.
         Manual,
 
         // Restore when resources are available.
         WhenAvailable,
 
-        // Restore as soon as possible.
+        // Restore as soon as possible, but only when
+        // the canvas is visible.
         Auto
     };
     void loseContext(LostContextMode) override;
     void forceLostContext(LostContextMode, AutoRecoveryMethod);
     void forceRestoreContext();
     void loseContextImpl(LostContextMode, AutoRecoveryMethod);
 
     WebGraphicsContext3D* webContext() const { return drawingBuffer()->context(); }
     WebGLContextGroup* contextGroup() const { return m_contextGroup.get(); }
     Extensions3DUtil* extensionsUtil();
@@ skipping 104 matching lines @@
 
     PassRefPtr<Image> videoFrameToImage(HTMLVideoElement*);
 
     // Structure for rendering to a DrawingBuffer, instead of directly
     // to the back-buffer of m_context.
     RefPtr<DrawingBuffer> m_drawingBuffer;
     DrawingBuffer* drawingBuffer() const;
 
     RefPtr<WebGLContextGroup> m_contextGroup;
 
+    bool m_isHidden;
     LostContextMode m_contextLostMode;
     AutoRecoveryMethod m_autoRecoveryMethod;
     // Dispatches a context lost event once it is determined that one is needed.
     // This is used for synthetic, WEBGL_lose_context and real context losses. For real ones, it's
     // likely that there's no JavaScript on the stack, but that might be dependent
     // on how exactly the platform discovers that the context was lost. For better
     // portability we always defer the dispatch of the event.
     Timer<WebGLRenderingContextBase> m_dispatchContextLostEventTimer;
     bool m_restoreAllowed;
     Timer<WebGLRenderingContextBase> m_restoreTimer;
@@ skipping 587 matching lines @@
 #endif
 };
 
 DEFINE_TYPE_CASTS(WebGLRenderingContextBase, CanvasRenderingContext, context, context->is3d(), context.is3d());
 
 } // namespace blink
 
 WTF_ALLOW_MOVE_INIT_AND_COMPARE_WITH_MEM_FUNCTIONS(blink::WebGLRenderingContextBase::TextureUnitState);
 
 #endif // WebGLRenderingContextBase_h