[Explore Sites]: Add missing UserActions UMA reporting for the next round of experiments.

Change-Id: I5f4a016bb924eaf227f4df23b1ffae37bc02cc87
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1625815
Commit-Queue: Justin DeWitt <dewittj@chromium.org>
Reviewed-by: Justin DeWitt <dewittj@chromium.org>
Reviewed-by: Brian White <bcwhite@chromium.org>
Cr-Commit-Position: refs/heads/master@{#662824}

chrome/android/java/src/org/chromium/chrome/browser/explore_sites/ExploreSitesCategoryCardView.java

@@ -15,6 +15,7 @@ import android.widget.LinearLayout;
 import android.widget.TextView;
 
 import org.chromium.base.metrics.RecordHistogram;
+import org.chromium.base.metrics.RecordUserAction;
 import org.chromium.chrome.R;
 import org.chromium.chrome.browser.native_page.ContextMenuManager;
 import org.chromium.chrome.browser.native_page.NativePageNavigationDelegate;
@@ -86,6 +87,7 @@ public class ExploreSitesCategoryCardView extends LinearLayout {
         public void onClick(View view) {
             recordCategoryClick(mCategory.getType());
             recordTileIndexClick(mCategoryCardIndex, mTileIndex);
+            RecordUserAction.record("Android.ExploreSitesPage.ClickOnSiteIcon");
             ExploreSitesBridge.recordClick(mProfile, mSiteUrl, mCategory.getType());
             mNavigationDelegate.openUrl(WindowOpenDisposition.CURRENT_TAB,
                     new LoadUrlParams(getUrl(), PageTransition.AUTO_BOOKMARK));

chrome/android/java/src/org/chromium/chrome/browser/explore_sites/ExploreSitesPage.java

@@ -86,6 +86,7 @@ public class ExploreSitesPage extends BasicNativePage {
     private boolean mHasFetchedNetworkCatalog;
     private boolean mIsLoaded;
     private int mInitialScrollPosition;
+    private boolean mScrollUserActionReported;
 
     /**
      * Create a new instance of the explore sites page.
@@ -167,6 +168,19 @@ public class ExploreSitesPage extends BasicNativePage {
 
         mRecyclerView.setLayoutManager(mLayoutManager);
         mRecyclerView.setAdapter(adapter);
+        mRecyclerView.addOnScrollListener(new RecyclerView.OnScrollListener() {
+            @Override
+            public void onScrolled(RecyclerView v, int x, int y) {
+                // y=0 on initial layout, even if the initial scroll position is requested
+                // that is not 0. Once user starts scrolling via touch, the onScrolled comes
+                // in bunches with |y| having a dY value of every small move, positive (scroll
+                // down) or negative (scroll up) number of dps for each move.
+                if (!mScrollUserActionReported && (y != 0)) {
+                    mScrollUserActionReported = true;
+                    RecordUserAction.record("Android.ExploreSitesPage.Scrolled");
+                }
+            }
+        });
 
         // When we personalize, we don't want to scroll to the 4th category.
         mInitialScrollPosition =

tools/metrics/actions/actions.xml

@@ -1784,6 +1784,13 @@ should be able to be added at any place in this file.
   <description>User opened NTP with enabled ExploreSites section.</description>
 </action>
 
+<action name="Android.ExploreSitesPage.ClickOnSiteIcon">
+  <owner>dimich@chromium.org</owner>
+  <description>
+    User clicked on a site icon while on ExploreSites page.
+  </description>
+</action>
+
 <action name="Android.ExploreSitesPage.Open">
   <owner>dimich@chromium.org</owner>
   <description>
@@ -1791,6 +1798,14 @@ should be able to be added at any place in this file.
   </description>
 </action>
 
+<action name="Android.ExploreSitesPage.Scrolled">
+  <owner>dimich@chromium.org</owner>
+  <description>
+    User scrolled the ExploreSites page. Reported once per ExploreSitesPage
+    instance shown.
+  </description>
+</action>
+
 <action name="Android.HistoryPage.ClearBrowsingData">
   <owner>twellington@chromium.org</owner>
   <description>