commit 5c9311ed7789a0591420b9b4b46cab5519651caa
author pkotwicz <pkotwicz@chromium.org> Thu Jun 29 21:08:55 2017
committer Commit Bot <commit-bot@chromium.org> Thu Jun 29 21:08:55 2017
tree adac287ab5c88bd36c0dc8dd60c793a38ef49bd5
parent fd94c00a57085279ce96fc861e41bee1eae2fcac

Add UMA metric to track the time elapsed since a WebAPK was last launched

This CL also:
Adds a new SharedPreferences property "has_been_launched" to track whether the
WebAPK/Webapp has been launched from the home screen.

BUG=730201
Test=WebApkIntegrationTest.*, WebappModeTest.*

Review-Url: https://codereview.chromium.org/2930553002
Cr-Commit-Position: refs/heads/master@{#483485}

base/android/java/src/org/chromium/base/metrics/RecordHistogram.java

diff --git a/base/android/java/src/org/chromium/base/metrics/RecordHistogram.java b/base/android/java/src/org/chromium/base/metrics/RecordHistogram.java
index eaf57b7..b3667c55 100644
--- a/base/android/java/src/org/chromium/base/metrics/RecordHistogram.java
+++ b/base/android/java/src/org/chromium/base/metrics/RecordHistogram.java
@@ -270,6 +270,15 @@
     }
 
     /**
+     * Returns the number of samples recorded for the given histogram.
+     * @param name name of the histogram to look up.
+     */
+    @VisibleForTesting
+    public static int getHistogramTotalCountForTesting(String name) {
+        return nativeGetHistogramTotalCountForTesting(name);
+    }
+
+    /**
      * Initializes the metrics system.
      */
     public static void initialize() {
@@ -290,5 +299,6 @@
     private static native long nativeRecordSparseHistogram(String name, long key, int sample);
 
     private static native int nativeGetHistogramValueCountForTesting(String name, int sample);
+    private static native int nativeGetHistogramTotalCountForTesting(String name);
     private static native void nativeInitialize();
 }

base/android/record_histogram.cc

diff --git a/base/android/record_histogram.cc b/base/android/record_histogram.cc
index 1a207a18..0561986 100644
--- a/base/android/record_histogram.cc
+++ b/base/android/record_histogram.cc
@@ -315,6 +315,20 @@
   return samples->GetCount(static_cast<int>(sample));
 }
 
+jint GetHistogramTotalCountForTesting(
+    JNIEnv* env,
+    const JavaParamRef<jclass>& clazz,
+    const JavaParamRef<jstring>& histogram_name) {
+  HistogramBase* histogram = StatisticsRecorder::FindHistogram(
+      android::ConvertJavaStringToUTF8(env, histogram_name));
+  if (histogram == nullptr) {
+    // No samples have been recorded for this histogram.
+    return 0;
+  }
+
+  return histogram->SnapshotSamples()->TotalCount();
+}
+
 bool RegisterRecordHistogram(JNIEnv* env) {
   return RegisterNativesImpl(env);
 }