Length returned from glGetUniform*RobustANGLE should be in values, not bytes.

BUG=angleproject:1354

Change-Id: I805499c3514a8b323e9864b7cf9100814f3d5cc5
Reviewed-on: https://chromium-review.googlesource.com/411420
Reviewed-by: Corentin Wallez <cwallez@chromium.org>
Commit-Queue: Geoff Lang <geofflang@chromium.org>
diff --git a/src/libANGLE/validationES.cpp b/src/libANGLE/validationES.cpp
index ce8a80a..eae0c35 100644
--- a/src/libANGLE/validationES.cpp
+++ b/src/libANGLE/validationES.cpp
@@ -3463,8 +3463,7 @@
 
     if (length)
     {
-        // Cast is safe because of comparison to bufSize.
-        *length = static_cast<GLsizei>(requiredBytes);
+        *length = VariableComponentCount(uniform.type);
     }
 
     return true;