Add recording of the root document height.

Add recording of AnchorElementMetrics.Clicked.RatioRootHeight.

Bug: 850624
Change-Id: Ia5ff57cc729cf7d577a59967f473c50da99e1e3b
Reviewed-on: https://chromium-review.googlesource.com/1157282Reviewed-by: Tarun Bansal <tbansal@chromium.org>
Reviewed-by: Kinuko Yasuda <kinuko@chromium.org>
Reviewed-by: Steven Holte <holte@chromium.org>
Commit-Queue: Lu Chen <chelu@chromium.org>
Cr-Commit-Position: refs/heads/master@{#579906}

third_party/blink/renderer/core/html/anchor_element_metrics.cc

@@ -182,6 +182,8 @@ base::Optional<AnchorElementMetrics> AnchorElementMetrics::Create(
                         ->GetScrollableArea()
                         ->ContentsSize()
                         .Height();
+  float ratio_root_height = root_height / base_height;
+
   int root_scrolled =
       root_frame_view->LayoutViewport()->ScrollOffsetInt().Height();
   float ratio_distance_root_bottom =
@@ -199,7 +201,7 @@ base::Optional<AnchorElementMetrics> AnchorElementMetrics::Create(
   return AnchorElementMetrics(
       anchor_element, ratio_area, ratio_visible_area,
       ratio_distance_top_to_visible_top, ratio_distance_center_to_visible_top,
-      ratio_distance_root_top, ratio_distance_root_bottom,
+      ratio_distance_root_top, ratio_distance_root_bottom, ratio_root_height,
       IsInIFrame(*anchor_element), ContainsImage(*anchor_element),
       IsSameHost(*anchor_element), IsUrlIncrementedByOne(*anchor_element));
 }
@@ -311,6 +313,10 @@ void AnchorElementMetrics::RecordMetricsOnClick() const {
       "AnchorElementMetrics.Clicked.RatioDistanceRootBottom",
       static_cast<int>(std::min(ratio_distance_root_bottom_, 100.0f) * 100));
 
+  UMA_HISTOGRAM_COUNTS_10000(
+      "AnchorElementMetrics.Clicked.RatioRootHeight",
+      static_cast<int>(std::min(ratio_root_height_, 100.0f) * 100));
+
   UMA_HISTOGRAM_BOOLEAN("AnchorElementMetrics.Clicked.IsInIFrame",
                         is_in_iframe_);
 

third_party/blink/renderer/core/html/anchor_element_metrics.h

@@ -88,6 +88,9 @@ class CORE_EXPORT AnchorElementMetrics {
   // height.
   const float ratio_distance_root_bottom_;
 
+  // The hight of the root document, divided by the viewport height.
+  const float ratio_root_height_;
+
   // Whether the anchor element is within an iframe.
   const bool is_in_iframe_;
 
@@ -108,6 +111,7 @@ class CORE_EXPORT AnchorElementMetrics {
                               float ratio_distance_center_to_visible_top,
                               float ratio_distance_root_top,
                               float ratio_distance_root_bottom,
+                              float ratio_root_height,
                               bool is_in_iframe,
                               bool contains_image,
                               bool is_same_host,
@@ -120,6 +124,7 @@ class CORE_EXPORT AnchorElementMetrics {
             ratio_distance_center_to_visible_top),
         ratio_distance_root_top_(ratio_distance_root_top),
         ratio_distance_root_bottom_(ratio_distance_root_bottom),
+        ratio_root_height_(ratio_root_height),
         is_in_iframe_(is_in_iframe),
         contains_image_(contains_image),
         is_same_host_(is_same_host),

tools/metrics/histograms/histograms.xml

@@ -717,6 +717,16 @@ uploading your change for review.
   </summary>
 </histogram>
 
+<histogram name="AnchorElementMetrics.Clicked.RatioRootHeight" units="%">
+  <owner>chelu@chromium.org</owner>
+  <owner>tbansal@chromium.org</owner>
+  <summary>
+    The ratio between the height of the root document and the height of the
+    viewport times 100. This histogram is recorded when the anchor element is
+    clicked.
+  </summary>
+</histogram>
+
 <histogram name="AnchorElementMetrics.Clicked.RatioSameHost_DiffHost" units="%">
   <owner>chelu@chromium.org</owner>
   <owner>tbansal@chromium.org</owner>