Scope ANGLE_UNUSED_VARIABLE.

Renames the macro to be more ANGLE-ey.

Refactoring only.

Bug: angleproject:1671
Change-Id: I8f2dd227c7e2025886ec66e85efa877ea261d0ad
Reviewed-on: https://chromium-review.googlesource.com/1036209
Reviewed-by: Yuly Novikov <ynovikov@chromium.org>
Commit-Queue: Jamie Madill <jmadill@chromium.org>
diff --git a/src/common/bitset_utils_unittest.cpp b/src/common/bitset_utils_unittest.cpp
index 3394890..fc2c752 100644
--- a/src/common/bitset_utils_unittest.cpp
+++ b/src/common/bitset_utils_unittest.cpp
@@ -55,7 +55,7 @@
     for (size_t bit : mStateBits)
     {
         sawBit = true;
-        UNUSED_VARIABLE(bit);
+        ANGLE_UNUSED_VARIABLE(bit);
     }
     EXPECT_FALSE(sawBit);
 }