Fix type in DM/mesa

TBR=mtklein@google.com

Review URL: https://codereview.chromium.org/269723004

git-svn-id: http://skia.googlecode.com/svn/trunk@14531 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/dm/DM.cpp b/dm/DM.cpp
index ef5c0f6..becdc50 100644
--- a/dm/DM.cpp
+++ b/dm/DM.cpp
@@ -70,7 +70,7 @@
 #endif
 static const GrContextFactory::GLContextType mesa   =
 #if SK_MESA
-GLContextFactory::kMESA_GLContextType;
+GrContextFactory::kMESA_GLContextType;
 #else
 native;
 #endif