Fixing Canvas2DLayerBridge to handle lost graphics contexts

Source/core/platform/graphics/Extensions3D.h

Index: Source/core/platform/graphics/Extensions3D.h
diff --git a/Source/core/platform/graphics/Extensions3D.h b/Source/core/platform/graphics/Extensions3D.h
index b1ddf791533f3b4b3f4a8081e6ba0586403637fd..f3866e6808b8bbe015d023db02ff7afa83bf7ec0 100644
--- a/Source/core/platform/graphics/Extensions3D.h
+++ b/Source/core/platform/graphics/Extensions3D.h
@@ -108,7 +108,7 @@ public:
         // 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,
@@ -315,6 +315,9 @@ public:
     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.