GLES1: gl(Enable|Disable)ClientState

+ Introduce the GL_OES_point_size_array extension for point size array
support.

BUG=angleproject:2306

Change-Id: Ib1a60b7dcd0497eb807f0d3c80bc95b4748d9a96
Reviewed-on: https://chromium-review.googlesource.com/1014282
Commit-Queue: Lingfeng Yang <lfy@google.com>
Reviewed-by: Geoff Lang <geofflang@chromium.org>
Reviewed-by: Corentin Wallez <cwallez@chromium.org>
diff --git a/src/libANGLE/Context.cpp b/src/libANGLE/Context.cpp
index 4b4f347..fada66e 100644
--- a/src/libANGLE/Context.cpp
+++ b/src/libANGLE/Context.cpp
@@ -2978,6 +2978,10 @@
 {
     mCaps = mImplementation->getNativeCaps();
 
+    mExtensions = mImplementation->getNativeExtensions();
+
+    mLimitations = mImplementation->getNativeLimitations();
+
     // GLES1 emulation: Initialize caps (Table 6.20 / 6.22 in the ES 1.1 spec)
     if (getClientVersion() < Version(2, 0))
     {
@@ -2987,12 +2991,11 @@
         mCaps.maxModelviewMatrixStackDepth  = Caps::GlobalMatrixStackDepth;
         mCaps.maxProjectionMatrixStackDepth = Caps::GlobalMatrixStackDepth;
         mCaps.maxTextureMatrixStackDepth    = Caps::GlobalMatrixStackDepth;
+
+        // Default extensions for GLES1
+        mExtensions.pointSizeArray = true;
     }
 
-    mExtensions = mImplementation->getNativeExtensions();
-
-    mLimitations = mImplementation->getNativeLimitations();
-
     if (getClientVersion() < Version(3, 0))
     {
         // Disable ES3+ extensions