SkVarAlloc::approxBytesAllocated()

This is what I was getting at on the other CL.

BUG=skia:

Committed: https://skia.googlesource.com/skia/+/f27f1bcce50c8f95aea8469684a70b70c9baee09

CQ_EXTRA_TRYBOTS=client.skia.android:Test-Android-Nexus5-Adreno330-Arm7-Release-Trybot

Review URL: https://codereview.chromium.org/730193003

1 files changed, 13 insertions, 0 deletions

diff --git a/tests/VarAllocTest.cpp b/tests/VarAllocTest.cpp
new file mode 100644
index 0000000000..d6a288dcce
--- /dev/null
+++ b/tests/VarAllocTest.cpp
@@ -0,0 +1,13 @@
+#include "Test.h"
+#include "SkVarAlloc.h"
+
+DEF_TEST(VarAlloc, r) {
+    SkVarAlloc va;
+    char* p = va.alloc(128, SK_MALLOC_THROW);
+    sk_bzero(p, 128);  // Just checking this is safe.
+
+#ifndef SK_BUILD_FOR_ANDROID
+    // This method will always return 0 on Android.
+    REPORTER_ASSERT(r, va.approxBytesAllocated() >= 128);
+#endif
+}