Add ES3.1 API constants

The newly added capability constants are handled in the corresponding
glGet functions. Also, getBooleani_v has been added.

BUG=angleproject:1442

TEST=angle_deqp_gtest_gles31_tests
--gtest_filter=*functional_state_query_integer_max_*
TEST=angle_deqp_gtest_gles31_tests
--gtest_filter=*state_query_indexed_max_compute_work_group_size*
TEST=angle_unittests
TEST=angle_end2end_tests

Change-Id: I846e006307563ae81d8b6c62cf261417e15186c7
Reviewed-on: https://chromium-review.googlesource.com/362270
Reviewed-by: Geoff Lang <geofflang@chromium.org>
Commit-Queue: Olli Etuaho <oetuaho@nvidia.com>
diff --git a/src/libANGLE/State.cpp b/src/libANGLE/State.cpp
index e5d0850..6c3f04d 100644
--- a/src/libANGLE/State.cpp
+++ b/src/libANGLE/State.cpp
@@ -1797,7 +1797,7 @@
     }
 }
 
-bool State::getIndexedIntegerv(GLenum target, GLuint index, GLint *data)
+void State::getIntegeri_v(GLenum target, GLuint index, GLint *data)
 {
     switch (target)
     {
@@ -1814,13 +1814,12 @@
         }
         break;
       default:
-        return false;
+          UNREACHABLE();
+          break;
     }
-
-    return true;
 }
 
-bool State::getIndexedInteger64v(GLenum target, GLuint index, GLint64 *data)
+void State::getInteger64i_v(GLenum target, GLuint index, GLint64 *data)
 {
     switch (target)
     {
@@ -1849,10 +1848,14 @@
         }
         break;
       default:
-        return false;
+          UNREACHABLE();
+          break;
     }
+}
 
-    return true;
+void State::getBooleani_v(GLenum target, GLuint index, GLboolean *data)
+{
+    UNREACHABLE();
 }
 
 bool State::hasMappedBuffer(GLenum target) const