Translator: Fix SPIR-V translation without "variables" flag

This flag is now assumed to always be true for the SPIR-V (and MSL)
translators.  They use the collected variables during translation.

Bug: chromium:1447314
Change-Id: I69d31ce8144aec0bd2a7263bad6e5a366e922740
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/4567830
Auto-Submit: Shahbaz Youssefi <syoussefi@chromium.org>
Reviewed-by: Geoff Lang <geofflang@chromium.org>
Commit-Queue: Shahbaz Youssefi <syoussefi@chromium.org>

src/compiler/translator/TranslatorVulkan.h

diff --git a/src/compiler/translator/TranslatorVulkan.h b/src/compiler/translator/TranslatorVulkan.h
index 6939eb8..59a030b 100644
--- a/src/compiler/translator/TranslatorVulkan.h
+++ b/src/compiler/translator/TranslatorVulkan.h
@@ -32,6 +32,9 @@
                                  PerformanceDiagnostics *perfDiagnostics) override;
     bool shouldFlattenPragmaStdglInvariantAll() override;
 
+    // Need to collect variables so that RemoveInactiveInterfaceVariables works.
+    bool shouldCollectVariables(const ShCompileOptions &compileOptions) override { return true; }
+
     [[nodiscard]] bool translateImpl(TIntermBlock *root,
                                      const ShCompileOptions &compileOptions,
                                      PerformanceDiagnostics *perfDiagnostics,

src/tests/gl_tests/GLSLTest.cpp

diff --git a/src/tests/gl_tests/GLSLTest.cpp b/src/tests/gl_tests/GLSLTest.cpp
index 1d88a2a..c003cc0 100644
--- a/src/tests/gl_tests/GLSLTest.cpp
+++ b/src/tests/gl_tests/GLSLTest.cpp
@@ -1038,6 +1038,21 @@
     ANGLE_GL_PROGRAM(program, essl1_shaders::vs::Simple(), kFS);
 }
 
+// Test that inactive uniforms of struct type don't cause any errors.
+TEST_P(GLSLTest, InactiveStructUniform)
+{
+    constexpr char kVS[] = R"(
+uniform struct
+{
+    vec4 c;
+} s;
+void main()
+{
+})";
+
+    ANGLE_GL_PROGRAM(program, kVS, essl1_shaders::fs::Red());
+}
+
 // Test that struct with same name can be declared in inner scope.
 TEST_P(GLSLTest, SameNameStructInInnerScope)
 {