Add support for IMG's MSAA extension.

src/gpu/gl/android/GrGLCreateNativeInterface_android.cpp

Index: src/gpu/gl/android/GrGLCreateNativeInterface_android.cpp
===================================================================
--- src/gpu/gl/android/GrGLCreateNativeInterface_android.cpp	(revision 8240)
+++ src/gpu/gl/android/GrGLCreateNativeInterface_android.cpp	(working copy)
@@ -124,6 +124,10 @@
         interface->fDeleteRenderbuffers = glDeleteRenderbuffers;
         interface->fFramebufferRenderbuffer = glFramebufferRenderbuffer;
         interface->fFramebufferTexture2D = glFramebufferTexture2D;
+#if GL_IMG_multisampled_render_to_texture
+        interface->fFramebufferTexture2DMultisample = glFramebufferTexture2DMultisampleIMG;
+        interface->fRenderbufferStorageMultisample = glRenderbufferStorageMultisampleIMG;
+#endif
         interface->fGenFramebuffers = glGenFramebuffers;
         interface->fGenRenderbuffers = glGenRenderbuffers;
         interface->fGetFramebufferAttachmentParameteriv = glGetFramebufferAttachmentParameteriv;