Populate EEP estimate in NQE

tools/metrics/histograms/histograms.xml

Index: tools/metrics/histograms/histograms.xml
diff --git a/tools/metrics/histograms/histograms.xml b/tools/metrics/histograms/histograms.xml
index 9a6492082af05bcf379ffede59e7d5f9f65ad7cd..c9409501b81a6309c2bf1600aae6619df589395d 100644
--- a/tools/metrics/histograms/histograms.xml
+++ b/tools/metrics/histograms/histograms.xml
@@ -28450,6 +28450,18 @@ http://cs/file:chrome/histograms.xml - but prefer this file for new entries.
   </summary>
 </histogram>
 
+<histogram name="NQE.ExternalEstimateProviderStatus"
+    enum="NQEExternalEstimateProviderStatus">
+  <owner>bengr@chromium.org</owner>
+  <owner>tbansal@chromium.org</owner>
+  <summary>
+    Records the interaction (availability and query count) of Network Quality
+    Estimator with external estimates provider. Logged on network change events,
+    everytime external estimate provider is queried for an updated estimate, and
+    when it proactively notifies that an updated estimate is available.
+  </summary>
+</histogram>
+
 <histogram name="NQE.FastestRTT" units="milliseconds">
   <owner>bengr@chromium.org</owner>
   <owner>tbansal@chromium.org</owner>
@@ -66656,6 +66668,14 @@ To add a new entry, add it with any value and run test to compute valid value.
   <int value="2" label="Enabled">NPAPI is enabled</int>
 </enum>
 
+<enum name="NQEExternalEstimateProviderStatus" type="int">
+  <int value="0" label="External estimate provider was not available"/>
+  <int value="1" label="External estimate provider was available"/>
+  <int value="2" label="External estimate provider was queried"/>
+  <int value="3" label="Query to external estimate provider was successful"/>
+  <int value="4" label="Callback received from external estimate provider"/>
+</enum>
+
 <enum name="NtpFollowAction" type="int">
   <int value="0" label="PAGE_TRANSITION_LINK"/>
   <int value="1" label="PAGE_TRANSITION_TYPED"/>