503         fHeader.writeText("#extension ");  in writeFunctionCall()
504         fHeader.writeText(fProgram.fSettings.fCaps->shaderDerivativeExtensionString());  in writeFunctionCall()
505         fHeader.writeText(" : require\n");  in writeFunctionCall()
626                 fHeader.writeText("#extension ");  in writeFragCoord()
627                 fHeader.writeText(extension);  in writeFragCoord()
628                 fHeader.writeText(" : require\n");  in writeFragCoord()
630             fHeader.writeText("layout(origin_upper_left) in vec4 gl_FragCoord;\n");  in writeFragCoord()
642             fHeader.writeText("uniform ");  in writeFragCoord()
643             fHeader.writeText(precision);  in writeFragCoord()
644             fHeader.writeText("float " SKSL_RTHEIGHT_NAME ";\n");  in writeFragCoord()
1061                 fHeader.writeText("#extension ");  in writeVarDeclarations()
1062                 fHeader.writeText(fProgram.fSettings.fCaps->imageLoadStoreExtensionString());  in writeVarDeclarations()
1063                 fHeader.writeText(" : require\n");  in writeVarDeclarations()
1280                     fHeader.writeText("#extension ");  in writeProgramElement()
1281                     fHeader.writeText(fProgram.fSettings.fCaps->gsInvocationsExtensionString());  in writeProgramElement()
1282                     fHeader.writeText(" : require\n");  in writeProgramElement()
1300     fOut = &fHeader;  in generateCode()
1305         fHeader.writeText("#extension ");  in generateCode()
1306         fHeader.writeText(fProgram.fSettings.fCaps->geometryShaderExtensionString());  in generateCode()
1307         fHeader.writeText(" : require\n");  in generateCode()
1316     write_stringstream(fHeader, *rawOut);  in generateCode()