Add support for ES3 MSAA.

R=robertphillips@google.com, jvanverth@google.com

Author: bsalomon@google.com

Review URL: https://chromiumcodereview.appspot.com/23404002

git-svn-id: http://skia.googlecode.com/svn/trunk@11124 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/src/gpu/gl/GrGLCaps.h b/src/gpu/gl/GrGLCaps.h
index a4d5673..a05d2b6 100644
--- a/src/gpu/gl/GrGLCaps.h
+++ b/src/gpu/gl/GrGLCaps.h
@@ -54,7 +54,7 @@
          */
         kNone_MSFBOType = 0,
         /**
-         * GL3.0-style MSAA FBO (GL_ARB_framebuffer_object)
+         * GL3.0-style MSAA FBO (GL_ARB_framebuffer_object). 
          */
         kDesktop_ARB_MSFBOType,
         /**
@@ -62,6 +62,10 @@
          */
         kDesktop_EXT_MSFBOType,
         /**
+         * Similar to kDesktop_ARB but with additional restrictions on glBlitFramebuffer.
+         */
+        kES_3_0_MSFBOType,
+        /**
          * GL_APPLE_framebuffer_multisample ES extension
          */
         kES_Apple_MSFBOType,