[Merge to 3071] Change name of recently introduced metric Memory.Gpu.PhysicalFootprint.MacOS.

chrome/browser/metrics/metrics_memory_details.cc

Index: chrome/browser/metrics/metrics_memory_details.cc
diff --git a/chrome/browser/metrics/metrics_memory_details.cc b/chrome/browser/metrics/metrics_memory_details.cc
index d0e5ceb25631957bf497dfbba34aa96ef78993b2..1ba164c11e5636a809faf41812297d4f6d804727 100644
--- a/chrome/browser/metrics/metrics_memory_details.cc
+++ b/chrome/browser/metrics/metrics_memory_details.cc
@@ -179,7 +179,7 @@ void MetricsMemoryDetails::UpdateHistograms() {
         // Physical footprint was introduced in macOS 10.11.
         if (base::mac::IsAtLeastOS10_11()) {
           UMA_HISTOGRAM_MEMORY_LARGE_MB(
-              "Memory.Gpu.PhysicalFootprint.MacOS",
+              "Memory.Experimental.Gpu.PhysicalFootprint.MacOS",
               browser.processes[index].phys_footprint / 1024 / 1024);
         }
 #endif