Add missing break in switch.

Also replace some extension enums with core ones.

Bug chromium:805881

Change-Id: I80a9b658fb8dda9c759c4d79b89fbe71b8b91ae1
Reviewed-on: https://swiftshader-review.googlesource.com/16728
Tested-by: Nicolas Capens <nicolascapens@google.com>
Reviewed-by: Alexis Hétu <sugoi@google.com>
diff --git a/src/OpenGL/libGLESv2/libGLESv3.cpp b/src/OpenGL/libGLESv2/libGLESv3.cpp
index e22b252..056ef53 100644
--- a/src/OpenGL/libGLESv2/libGLESv3.cpp
+++ b/src/OpenGL/libGLESv2/libGLESv3.cpp
@@ -3860,6 +3860,7 @@
 		case GL_DRAW_FRAMEBUFFER:
 		case GL_FRAMEBUFFER:
 			framebuffer = context->getDrawFramebuffer();
+			break;
 		case GL_READ_FRAMEBUFFER:
 			framebuffer = context->getReadFramebuffer();
 			break;