Small cleanups suggested by ClangTidy

Bug: skia:
Cq-Include-Trybots: skia.primary:Test-Debian9-Clang-GCE-CPU-AVX2-x86_64-Release-All-SKNX_NO_SIMD
Change-Id: Idd95e359838fdaecbdccc3a2c5a1b36971f20b8b
Reviewed-on: https://skia-review.googlesource.com/113703
Reviewed-by: Mike Klein <mtklein@google.com>
Commit-Queue: Kevin Lubick <kjlubick@google.com>
diff --git a/tests/DrawOpAtlasTest.cpp b/tests/DrawOpAtlasTest.cpp
index e45ef52..ef219d9 100644
--- a/tests/DrawOpAtlasTest.cpp
+++ b/tests/DrawOpAtlasTest.cpp
@@ -28,10 +28,10 @@
     return count;
 }
 
-void GrAtlasManager::setMaxPages_TestingOnly(uint32_t numPages) {
+void GrAtlasManager::setMaxPages_TestingOnly(uint32_t maxPages) {
     for (int i = 0; i < kMaskFormatCount; i++) {
         if (fAtlases[i]) {
-            fAtlases[i]->setMaxPages_TestingOnly(numPages);
+            fAtlases[i]->setMaxPages_TestingOnly(maxPages);
         }
     }
 }