Handle ANGLE_multiview state queries

The patch extends glGetIntegerv and glGetFramebufferAttachmentParameteriv
logic to handle the new tokens from the ANGLE_multiview extension.

BUG=angleproject:2062
TEST=angle_end2end_tests

Change-Id: Ide145279cd7b58cd03502458d7d3a1a0f5e9e86d
Reviewed-on: https://chromium-review.googlesource.com/573780
Reviewed-by: Olli Etuaho <oetuaho@nvidia.com>
Reviewed-by: Geoff Lang <geofflang@chromium.org>
Commit-Queue: Olli Etuaho <oetuaho@nvidia.com>
diff --git a/src/libANGLE/Context.cpp b/src/libANGLE/Context.cpp
index 67492fa..d255bd8 100644
--- a/src/libANGLE/Context.cpp
+++ b/src/libANGLE/Context.cpp
@@ -1522,6 +1522,11 @@
             *params = mExtensions.maxLabelLength;
             break;
 
+        // GL_ANGLE_multiview
+        case GL_MAX_VIEWS_ANGLE:
+            *params = mExtensions.maxViews;
+            break;
+
         // GL_EXT_disjoint_timer_query
         case GL_GPU_DISJOINT_EXT:
             *params = mImplementation->getGPUDisjoint();