Micro-optimize ValidateDrawBase.

This speeds up our draw call benchmark.

BUG=angleproject:959

Change-Id: I9a916a6c344493cc96873ae5f4ec337c181dc487
Reviewed-on: https://chromium-review.googlesource.com/266026
Reviewed-by: Geoff Lang <geofflang@chromium.org>
Reviewed-by: Brandon Jones <bajones@chromium.org>
Tested-by: Jamie Madill <jmadill@chromium.org>
diff --git a/src/libANGLE/Program.h b/src/libANGLE/Program.h
index 38fc83d..0afa572 100644
--- a/src/libANGLE/Program.h
+++ b/src/libANGLE/Program.h
@@ -135,6 +135,7 @@
 
     GLuint getAttributeLocation(const std::string &name);
     int getSemanticIndex(int attributeIndex);
+    const int *getSemanticIndexes() const;
 
     void getActiveAttribute(GLuint index, GLsizei bufsize, GLsizei *length, GLint *size, GLenum *type, GLchar *name);
     GLint getActiveAttributeCount();