Send UMA about requested window state from tabs API

chrome/browser/extensions/api/tabs/tabs_api.cc

Index: chrome/browser/extensions/api/tabs/tabs_api.cc
diff --git a/chrome/browser/extensions/api/tabs/tabs_api.cc b/chrome/browser/extensions/api/tabs/tabs_api.cc
index d20aa05375795737ea042cc6fdd18131eb6ba6db..b07aacc5589b7bd3fde1dba811f78e4b327d3d39 100644
--- a/chrome/browser/extensions/api/tabs/tabs_api.cc
+++ b/chrome/browser/extensions/api/tabs/tabs_api.cc
@@ -17,6 +17,7 @@
 #include "base/logging.h"
 #include "base/memory/ptr_util.h"
 #include "base/memory/ref_counted_memory.h"
+#include "base/metrics/histogram_macros.h"
 #include "base/single_thread_task_runner.h"
 #include "base/stl_util.h"
 #include "base/strings/pattern.h"
@@ -199,6 +200,11 @@ void AssignOptionalValue(const std::unique_ptr<T>& source,
   }
 }
 
+void ReportRequestedWindowState(windows::WindowState state) {
+  UMA_HISTOGRAM_ENUMERATION("TabsApi.RequestedWindowState", state,

[Mark P, 2017/03/28 18:23:46]

It appears this enum comes from
out/Debug/gen/chrome/common/extensions/api/windows.h
which is auto-generated from
chrome/common/extensions/api/windows.json
It looks like that latter file allows comments.

Can you please put the standard warning label about not changing or deleting any
values in the enum?
https://chromium.googlesource.com/chromium/src.git/+/HEAD/tools/metrics/histo...

[afakhry, 2017/03/28 20:43:16]

Hmm, but that's the whole point of this CL though. We're adding this UMA to help
determine when we can remove one of the deprecated values "docked" in that enum,
so that it is no longer exposed to extensions.

Is there another approach?

[Mark P, 2017/03/28 21:02:44]

You could put in a warning label that says if something is removed, then this
histogram will become unvalid and should be removed from the code and marked as
obsolete in histograms.xml.

[afakhry, 2017/03/29 00:51:29]

Done. Please take a look. Thanks!

+                            windows::WINDOW_STATE_LAST + 1);
+}
+
 ui::WindowShowState ConvertToWindowShowState(windows::WindowState state) {
   switch (state) {
     case windows::WINDOW_STATE_NORMAL:
@@ -489,6 +495,10 @@ ExtensionFunction::ResponseAction WindowsCreateFunction::Run() {
   std::string extension_id;
 
   if (create_data) {
+    // Report UMA stats to decide when to remove the deprecated "docked" windows
+    // state (crbug.com/703733).
+    ReportRequestedWindowState(create_data->state);
+
     // Figure out window type before figuring out bounds so that default
     // bounds can be set according to the window type.
     switch (create_data->type) {
@@ -669,6 +679,10 @@ ExtensionFunction::ResponseAction WindowsUpdateFunction::Run() {
     return RespondNow(Error(error));
   }
 
+  // Report UMA stats to decide when to remove the deprecated "docked" windows
+  // state (crbug.com/703733).
+  ReportRequestedWindowState(params->update_info.state);
+
   ui::WindowShowState show_state =
       ConvertToWindowShowState(params->update_info.state);