Use const reference when possible

src/libANGLE/Context.h

@@ -247,7 +247,7 @@ class StateCache final : angle::NonCopyable
 
     // Places that can trigger updateActiveImageUnitIndices:
     // 1. onProgramExecutableChange.
-    ImageUnitMask getActiveImageUnitIndices() const { return mCachedActiveImageUnitIndices; }
+    const ImageUnitMask &getActiveImageUnitIndices() const { return mCachedActiveImageUnitIndices; }
 
     // Places that can trigger updateCanDraw:
     // 1. onProgramExecutableChange.

src/libANGLE/State.cpp

@@ -589,7 +589,7 @@ void State::reset(const Context *context)
     setAllDirtyBits();
 }
 
-ANGLE_INLINE void State::unsetActiveTextures(ActiveTextureMask textureMask)
+ANGLE_INLINE void State::unsetActiveTextures(const ActiveTextureMask &textureMask)
 {
     // Unset any relevant bound textures.
     for (size_t textureIndex : textureMask)

src/libANGLE/State.h

@@ -893,7 +893,7 @@ class State : angle::NonCopyable
   private:
     friend class Context;
 
-    void unsetActiveTextures(ActiveTextureMask textureMask);
+    void unsetActiveTextures(const ActiveTextureMask &textureMask);
     void setActiveTextureDirty(size_t textureIndex, Texture *texture);
     void updateTextureBinding(const Context *context, size_t textureIndex, Texture *texture);
     void updateActiveTextureStateOnSync(const Context *context,