Add UMA for testing whether device supports memory mapping APK files with executable permissions.

base/android/library_loader/library_loader_hooks.cc

Index: base/android/library_loader/library_loader_hooks.cc
diff --git a/base/android/library_loader/library_loader_hooks.cc b/base/android/library_loader/library_loader_hooks.cc
index a8c75e1310dc9c93f27f6f95b0f84fd6778de6d8..fd131fc15682254f6904085a30131928ffccd07f 100644
--- a/base/android/library_loader/library_loader_hooks.cc
+++ b/base/android/library_loader/library_loader_hooks.cc
@@ -76,7 +76,8 @@ static void RecordChromiumAndroidLinkerBrowserHistogram(
     JNIEnv* env,
     jclass clazz,
     jboolean is_using_browser_shared_relros,
-    jboolean load_at_fixed_address_failed) {
+    jboolean load_at_fixed_address_failed,
+    jboolean apk_memory_mapping_supported) {
   // For low-memory devices, record whether or not we successfully loaded the
   // browser at a fixed address. Otherwise just record a normal invocation.
   BrowserHistogramCode histogram_code;
@@ -89,6 +90,8 @@ static void RecordChromiumAndroidLinkerBrowserHistogram(
   UMA_HISTOGRAM_ENUMERATION("ChromiumAndroidLinker.BrowserStates",
                             histogram_code,
                             MAX_BROWSER_HISTOGRAM_CODE);
+  UMA_HISTOGRAM_BOOLEAN("ChromiumAndroidLinker.ApkMemoryMappingSupported",
+                        apk_memory_mapping_supported);
 }
 
 void SetLibraryLoadedHook(LibraryLoadedHook* func) {