Measure time spent during StrictMode violations.

chrome/android/java/src/org/chromium/chrome/browser/webapps/WebappDirectoryManager.java

Index: chrome/android/java/src/org/chromium/chrome/browser/webapps/WebappDirectoryManager.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/webapps/WebappDirectoryManager.java b/chrome/android/java/src/org/chromium/chrome/browser/webapps/WebappDirectoryManager.java
index faca7a5b0dc33994ef9642b12ab05651ba317f2b..3ff95864f3c7efd6966aa69a7e4523115af30353 100644
--- a/chrome/android/java/src/org/chromium/chrome/browser/webapps/WebappDirectoryManager.java
+++ b/chrome/android/java/src/org/chromium/chrome/browser/webapps/WebappDirectoryManager.java
@@ -14,16 +14,19 @@ import android.net.Uri;
 import android.os.AsyncTask;
 import android.os.Build;
 import android.os.StrictMode;
+import android.os.SystemClock;
 import android.text.TextUtils;
 
 import org.chromium.base.ApplicationStatus;
 import org.chromium.base.FileUtils;
 import org.chromium.base.Log;
+import org.chromium.base.metrics.RecordHistogram;
 import org.chromium.chrome.browser.document.DocumentUtils;
 
 import java.io.File;
 import java.util.HashSet;
 import java.util.Set;
+import java.util.concurrent.TimeUnit;
 import java.util.concurrent.atomic.AtomicBoolean;
 
 /**
@@ -160,10 +163,13 @@ public class WebappDirectoryManager {
         StrictMode.ThreadPolicy oldPolicy = StrictMode.allowThreadDiskReads();
         StrictMode.allowThreadDiskWrites();
         try {
+            long time = SystemClock.elapsedRealtime();
             File webappDirectory = new File(getBaseWebappDirectory(context), webappId);
             if (!webappDirectory.exists() && !webappDirectory.mkdir()) {
                 Log.e(TAG, "Failed to create web app directory.");
             }
+            RecordHistogram.recordTimesHistogram("Android.StrictMode.WebappDir",
+                    SystemClock.elapsedRealtime() - time, TimeUnit.MILLISECONDS);
             return webappDirectory;
         } finally {
             StrictMode.setThreadPolicy(oldPolicy);