Enabling sampling of UMA and crash reports on Android.

chrome/android/java/src/org/chromium/chrome/browser/preferences/privacy/PrivacyPreferencesManager.java

Index: chrome/android/java/src/org/chromium/chrome/browser/preferences/privacy/PrivacyPreferencesManager.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/preferences/privacy/PrivacyPreferencesManager.java b/chrome/android/java/src/org/chromium/chrome/browser/preferences/privacy/PrivacyPreferencesManager.java
index cc67d03db34b1e97576af014bacf33add19b263c..5583d97d47647145445861199a7293247302ac4f 100644
--- a/chrome/android/java/src/org/chromium/chrome/browser/preferences/privacy/PrivacyPreferencesManager.java
+++ b/chrome/android/java/src/org/chromium/chrome/browser/preferences/privacy/PrivacyPreferencesManager.java
@@ -29,6 +29,7 @@ public class PrivacyPreferencesManager implements CrashReportingPermissionManage
     private static final String PREF_NETWORK_PREDICTIONS = "network_predictions";
     private static final String PREF_BANDWIDTH_OLD = "prefetch_bandwidth";
     private static final String PREF_BANDWIDTH_NO_CELLULAR_OLD = "prefetch_bandwidth_no_cellular";
+    private static final String PREF_METRICS_IN_SAMPLE = "metrics_in_sample";

[Alexei Svitkine (slow), 2016/08/18 06:16:39]

Nit: Move this right below PREF_METRICS_REPORTING

[jwd, 2016/08/23 18:40:03]

Done.

     private static final String PREF_CELLULAR_EXPERIMENT = "cellular_experiment";
     private static final String ALLOW_PRERENDER_OLD = "allow_prefetch";
     private static final String PREF_PHYSICAL_WEB = "physical_web";
@@ -277,6 +278,24 @@ public class PrivacyPreferencesManager implements CrashReportingPermissionManage
     }
 
     /**
+     * Sets whether this client is eligible to send metrics. If they are, and there was user
+     * consent, then metrics and crashes would be reported.
+     */
+    public void setClientInMetricsSample(boolean inSample) {
+        mSharedPreferences.edit().putBoolean(PREF_METRICS_IN_SAMPLE, inSample).apply();
+    }
+
+    /**
+     * Checks whether this client is eligible to send metrics. If they are, and there was user
+     * consent, then metrics and crashes would be reported.
+     *
+     * @returns boolean Whether client is eligible to send metrics.
+     */
+    public boolean isClientInMetricsSample() {
+        return mSharedPreferences.getBoolean(PREF_METRICS_IN_SAMPLE, true);
+    }
+
+    /**
      * Sets the crash upload preference, which determines whether crash dumps will be uploaded
      * always, never, or only on wifi.
      *