Obsolete Ash.ImmersiveFullscreen.WindowType histogram entry

Its expiration dates from M77.

Also, the CL removes the enum class and the aura::Window
property associated solely with populating this histogram:

- chromeos::ImmersiveFullscreenController::WindowType
- chromeos::kImmersiveWindowType

BUG=1113900, 1138662
R=chromium-metrics-reviews@google.com, jamescook@chromium.org, sky@chromium.org

Change-Id: Ib4345da71a21f67f45ffeb4fd68cb8e168552bcd
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2476916
Commit-Queue: Antonio Gomes <tonikitoo@igalia.com>
Reviewed-by: Brian White <bcwhite@chromium.org>
Reviewed-by: James Cook <jamescook@chromium.org>
Reviewed-by: Scott Violet <sky@chromium.org>
Cr-Commit-Position: refs/heads/master@{#818241}

chrome/browser/ui/views/apps/chrome_native_app_window_views_aura_ash.cc

@@ -90,10 +90,6 @@ void ChromeNativeAppWindowViewsAuraAsh::InitializeWindow(
   aura::Window* window = GetNativeWindow();
   window->SetProperty(aura::client::kAppType,
                       static_cast<int>(ash::AppType::CHROME_APP));
-  window->SetProperty(
-      chromeos::kImmersiveWindowType,
-      static_cast<int>(
-          chromeos::ImmersiveFullscreenController::WINDOW_TYPE_PACKAGED_APP));
   // Fullscreen doesn't always imply immersive mode (see
   // ShouldEnableImmersive()).
   window->SetProperty(chromeos::kImmersiveImpliedByFullscreen, false);

chrome/browser/ui/views/frame/immersive_mode_controller_ash.cc

@@ -67,13 +67,6 @@ void ImmersiveModeControllerAsh::Init(BrowserView* browser_view) {
                    browser_view_->top_container());
 
   observed_windows_.Add(browser_view_->GetNativeWindow());
-
-  browser_view_->GetNativeWindow()->SetProperty(
-      chromeos::kImmersiveWindowType,
-      static_cast<int>(
-          browser_view_->browser()->deprecated_is_app()
-              ? chromeos::ImmersiveFullscreenController::WINDOW_TYPE_HOSTED_APP
-              : chromeos::ImmersiveFullscreenController::WINDOW_TYPE_BROWSER));
 }
 
 void ImmersiveModeControllerAsh::SetEnabled(bool enabled) {

chromeos/ui/base/window_properties.cc

@@ -5,9 +5,6 @@
 #include "chromeos/ui/base/window_properties.h"
 
 #include "chromeos/ui/base/window_state_type.h"
-// TODO(crbug.com/1138662): Remove this include and the associated property
-// and histogram entry.
-#include "chromeos/ui/frame/immersive/immersive_fullscreen_controller.h"  // nogncheck
 #include "ui/aura/window.h"
 
 namespace chromeos {
@@ -17,10 +14,6 @@ DEFINE_UI_CLASS_PROPERTY_KEY(bool, kImmersiveIsActive, false)
 DEFINE_OWNED_UI_CLASS_PROPERTY_KEY(gfx::Rect,
                                    kImmersiveTopContainerBoundsInScreen,
                                    nullptr)
-DEFINE_UI_CLASS_PROPERTY_KEY(
-    int,
-    kImmersiveWindowType,
-    ImmersiveFullscreenController::WindowType::WINDOW_TYPE_OTHER)
 
 DEFINE_UI_CLASS_PROPERTY_KEY(bool, kIsShowingInOverviewKey, false)
 

chromeos/ui/base/window_properties.h

@@ -40,11 +40,6 @@ COMPONENT_EXPORT(CHROMEOS_UI_BASE)
 extern const aura::WindowProperty<gfx::Rect*>* const
     kImmersiveTopContainerBoundsInScreen;
 
-// The type of window for logging immersive metrics. Type:
-// ImmersiveFullscreenController::WindowType.
-COMPONENT_EXPORT(CHROMEOS_UI_BASE)
-extern const aura::WindowProperty<int>* const kImmersiveWindowType;
-
 // If true, the window is currently showing in overview mode.
 COMPONENT_EXPORT(CHROMEOS_UI_BASE)
 extern const aura::WindowProperty<bool>* const kIsShowingInOverviewKey;

chromeos/ui/frame/immersive/immersive_fullscreen_controller.cc

@@ -7,7 +7,6 @@
 #include <set>
 
 #include "base/bind.h"
-#include "base/metrics/histogram_macros.h"
 #include "chromeos/ui/base/window_properties.h"
 #include "chromeos/ui/frame/immersive/immersive_context.h"
 #include "chromeos/ui/frame/immersive/immersive_focus_watcher.h"
@@ -766,15 +765,6 @@ void ImmersiveFullscreenController::UpdateEnabled() {
 
     delegate_->OnImmersiveFullscreenExited();
   }
-
-  if (enabled_) {
-    // TODO(https://crbug.com/1138662): Remove this expired histogram entry.
-    UMA_HISTOGRAM_ENUMERATION(
-        "Ash.ImmersiveFullscreen.WindowType",
-        static_cast<WindowType>(
-            widget_->GetNativeWindow()->GetProperty(kImmersiveWindowType)),
-        WINDOW_TYPE_COUNT);
-  }
 }
 
 void ImmersiveFullscreenController::EnableTouchInsets(bool enable) {

chromeos/ui/frame/immersive/immersive_fullscreen_controller.h

@@ -60,16 +60,6 @@ class COMPONENT_EXPORT(CHROMEOS_UI_FRAME) ImmersiveFullscreenController
       public views::ViewObserver,
       public ImmersiveRevealedLock::Delegate {
  public:
-  // The enum is used for an enumerated histogram. New items should be only
-  // added to the end.
-  enum WindowType {
-    WINDOW_TYPE_OTHER,
-    WINDOW_TYPE_BROWSER,
-    WINDOW_TYPE_HOSTED_APP,
-    WINDOW_TYPE_PACKAGED_APP,
-    WINDOW_TYPE_COUNT
-  };
-
   // How many pixels are reserved for touch-events towards the top of an
   // immersive-fullscreen window.
   static const int kImmersiveFullscreenTopEdgeInset;

tools/metrics/histograms/histograms_xml/ash/histograms.xml

@@ -712,6 +712,11 @@ reviews. Googlers can read more about this at go/gwsq-gerrit.
 
 <histogram name="Ash.ImmersiveFullscreen.WindowType" enum="WindowType"
     expires_after="M77">
+  <obsolete>
+    Removed 10/2020 in Issue 1138662 - its recording code was deleted. This
+    histogram entry was added long time ago, likely when immersive fullscreen
+    was first added (circa 2014), and there is no records of what was learned.
+  </obsolete>
   <owner>kuscher@google.com</owner>
   <summary>
     The type of the window which is put into immersive fullscreen. Immersive