GLES1: glMultiTexCoord4(f|x)

BUG=angleproject:2306

+ common validation for multitexturing units
+ clang-format

Change-Id: I6eb456c273490e85fc7008e7e11d15e22dd20276
Reviewed-on: https://chromium-review.googlesource.com/987298
Commit-Queue: Lingfeng Yang <lfy@google.com>
Reviewed-by: Corentin Wallez <cwallez@chromium.org>
Reviewed-by: Jamie Madill <jmadill@chromium.org>
diff --git a/src/libANGLE/State.cpp b/src/libANGLE/State.cpp
index da4f559..770aa90 100644
--- a/src/libANGLE/State.cpp
+++ b/src/libANGLE/State.cpp
@@ -1947,6 +1947,15 @@
             params[2]          = normal[2];
             break;
         }
+        case GL_CURRENT_TEXTURE_COORDS:
+        {
+            const auto &texcoord = mGLES1State.mCurrentTextureCoords[mActiveSampler];
+            params[0]            = texcoord.s;
+            params[1]            = texcoord.t;
+            params[2]            = texcoord.r;
+            params[3]            = texcoord.q;
+            break;
+        }
         default:
             UNREACHABLE();
             break;