Fixing Canvas2DLayerBridge to handle lost graphics contexts

Source/core/platform/graphics/Extensions3D.h

 /*
  * Copyright (C) 2011 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:
  *
  * 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
@@ skipping 90 matching lines @@
 
     // Takes full name of extension: for example, "GL_EXT_texture_format_BGRA8888".
     // Checks to see whether the given extension is actually enabled (see ensureEnabled).
     // Has no other side-effects.
     bool isEnabled(const String&);
 
     enum ExtensionsEnumType {
         // GL_EXT_texture_format_BGRA8888 enums
         BGRA_EXT = 0x80E1,
 
-        // GL_ARB_robustness enums
+        // GL_ARB_robustness/GL_CHROMIUM_lose_context enums
         GUILTY_CONTEXT_RESET_ARB = 0x8253,
         INNOCENT_CONTEXT_RESET_ARB = 0x8254,
         UNKNOWN_CONTEXT_RESET_ARB = 0x8255,
 
         // GL_EXT/OES_packed_depth_stencil enums
         DEPTH24_STENCIL8 = 0x88F0,
         
         // GL_ANGLE_framebuffer_blit names
         READ_FRAMEBUFFER = 0x8CA8,
         DRAW_FRAMEBUFFER = 0x8CA9,
@@ skipping 186 matching lines @@
     void getQueryObjectuivEXT(Platform3DObject, GC3Denum, GC3Duint*);
 
     // GL_CHROMIUM_shallow_flush
     void shallowFlushCHROMIUM();
 
     // GL_ANGLE_instanced_arrays
     void drawArraysInstancedANGLE(GC3Denum mode, GC3Dint first, GC3Dsizei count, GC3Dsizei primcount);
     void drawElementsInstancedANGLE(GC3Denum mode, GC3Dsizei count, GC3Denum type, GC3Dintptr offset, GC3Dsizei primcount);
     void vertexAttribDivisorANGLE(GC3Duint index, GC3Duint divisor);
 
+    // GL_CHROMIUM_lose_context
+    void loseContextCHROMIUM(GC3Denum, GC3Denum);
+
 private:
     // Instances of this class are strictly owned by the GraphicsContext3D implementation and do not
     // need to be instantiated by any other code.
     friend class GraphicsContext3D;
     explicit Extensions3D(GraphicsContext3D*);
 
     // Weak pointer back to GraphicsContext3D.
     GraphicsContext3D* m_context;
 };
 
 } // namespace WebCore
 
 #endif // Extensions3D_h