Add UMA metrics collection for text filtering in Ash overview mode

Add four new histograms to Ash.WindowSelector:

* Ash.WindowSelector.ItemsWhenTextFilteringUsed: 
  Records the number of items visible in overview mode
  sessions where the text filtering feature is used.

* Ash.WindowSelector.TextFilteringStringLength:
  Records the length of the string in the text filtering
  textfield at the time when the overview mode session
  is terminated.

* Ash.WindowSelector.TextFilteringTextfieldCleared:
  Records the number of times the text in the text
  filtering textfield has been completely removed,
  recorded at the time when the overview mode session
  is terminated.

* Ash.WindowSelector.TimeInOverviewWithTextFiltering:
  Records the time spent in an overview mode sessions
  where the text filtering feature is used.

BUG=398156
TEST=none

Review URL: https://codereview.chromium.org/427673002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@286313 0039d316-1c4b-4281-b951-d872f2087c98

ash/wm/overview/window_selector.cc

@@ -153,7 +153,9 @@ WindowSelector::WindowSelector(const WindowList& windows,
       overview_start_time_(base::Time::Now()),
       num_key_presses_(0),
       num_items_(0),
-      showing_selection_widget_(false) {
+      showing_selection_widget_(false),
+      text_filter_string_length_(0),
+      num_times_textfield_cleared_(0) {
   DCHECK(delegate_);
   Shell* shell = Shell::GetInstance();
   shell->OnOverviewModeStarting();
@@ -244,6 +246,20 @@ WindowSelector::~WindowSelector() {
   UMA_HISTOGRAM_MEDIUM_TIMES("Ash.WindowSelector.TimeInOverview",
                              base::Time::Now() - overview_start_time_);
 
+  // Record metrics related to text filtering.
+  UMA_HISTOGRAM_COUNTS_100("Ash.WindowSelector.TextFilteringStringLength",
+                           text_filter_string_length_);
+  UMA_HISTOGRAM_COUNTS_100("Ash.WindowSelector.TextFilteringTextfieldCleared",
+                           num_times_textfield_cleared_);
+  if (text_filter_string_length_) {
+    UMA_HISTOGRAM_MEDIUM_TIMES(
+        "Ash.WindowSelector.TimeInOverviewWithTextFiltering",
+        base::Time::Now() - overview_start_time_);
+    UMA_HISTOGRAM_COUNTS_100(
+        "Ash.WindowSelector.ItemsWhenTextFilteringUsed",
+        remaining_items);
+  }
+
   // TODO(flackr): Change this to OnOverviewModeEnded and move it to when
   // everything is done.
   shell->OnOverviewModeEnding();
@@ -389,6 +405,10 @@ void WindowSelector::ContentsChanged(views::Textfield* sender,
     return;
   }
 
+  text_filter_string_length_ = new_contents.length();
+  if (!text_filter_string_length_)
+    num_times_textfield_cleared_++;
+
   bool should_show_selection_widget = !new_contents.empty();
   if (showing_selection_widget_ != should_show_selection_widget) {
     ui::ScopedLayerAnimationSettings animation_settings(

ash/wm/overview/window_selector.h

@@ -159,6 +159,13 @@ class ASH_EXPORT WindowSelector
   // such as enter key to select.
   scoped_ptr<views::Widget> text_filter_widget_;
 
+  // The current length of the string entered into the text filtering textfield.
+  size_t text_filter_string_length_;
+
+  // The number of times the text filtering textfield has been cleared of text
+  // during this overview mode session.
+  size_t num_times_textfield_cleared_;
+
   DISALLOW_COPY_AND_ASSIGN(WindowSelector);
 };
 

tools/metrics/histograms/histograms.xml

@@ -764,6 +764,16 @@ Therefore, the affected-histogram name has to have at least one dot in it.
   </summary>
 </histogram>
 
+<histogram name="Ash.WindowSelector.ItemsWhenTextFilteringUsed" units="items">
+  <owner>tdanderson@chromium.org</owner>
+  <owner>flackr@chromium.org</owner>
+  <summary>
+    The number of items showing in overview mode at the moment when an item is
+    selected or when selection is canceled. Only recorded if the text filtering
+    textfield contains a non-empty string.
+  </summary>
+</histogram>
+
 <histogram name="Ash.WindowSelector.KeyPressesOverItemsRatio" units="%">
   <owner>flackr@chromium.org</owner>
   <owner>tdanderson@chromium.org</owner>
@@ -781,6 +791,27 @@ Therefore, the affected-histogram name has to have at least one dot in it.
   </summary>
 </histogram>
 
+<histogram name="Ash.WindowSelector.TextFilteringStringLength"
+    units="characters">
+  <owner>tdanderson@chromium.org</owner>
+  <owner>flackr@chromium.org</owner>
+  <summary>
+    The length of the string entered into the text filtering textfield at the
+    moment when an item is selected or when selection is canceled.
+  </summary>
+</histogram>
+
+<histogram name="Ash.WindowSelector.TextFilteringTextfieldCleared">
+  <owner>tdanderson@chromium.org</owner>
+  <owner>flackr@chromium.org</owner>
+  <summary>
+    The number of times the text filtering textfield has had all of its text
+    removed within a single overview mode session. Measured from the time
+    overview mode is invoked to when an item is selected or when selection is
+    canceled.
+  </summary>
+</histogram>
+
 <histogram name="Ash.WindowSelector.TimeBetweenUse" units="milliseconds">
   <owner>flackr@chromium.org</owner>
   <owner>kuscher@google.com</owner>
@@ -800,6 +831,18 @@ Therefore, the affected-histogram name has to have at least one dot in it.
   </summary>
 </histogram>
 
+<histogram name="Ash.WindowSelector.TimeInOverviewWithTextFiltering"
+    units="milliseconds">
+  <owner>tdanderson@chromium.org</owner>
+  <owner>flackr@chromium.org</owner>
+  <summary>
+    The amount of time spent in overview mode when text filtering is used. The
+    time is measured from the moment the windows begin animating to a thumbnail
+    size preview to when a window is selected or selection is canceled. Only
+    recorded if the text filtering textfield contains a non-empty string.
+  </summary>
+</histogram>
+
 <histogram name="AsyncDNS.AttemptCountFail">
   <owner>Please list the metric's owners. Add more owner tags as needed.</owner>
   <summary>