cocoa: add --use-views-task-manager

chrome/browser/ui/cocoa/task_manager_mac.mm

Index: chrome/browser/ui/cocoa/task_manager_mac.mm
diff --git a/chrome/browser/ui/cocoa/task_manager_mac.mm b/chrome/browser/ui/cocoa/task_manager_mac.mm
index 178681ab230a6f625c119ebee54dc5451fbf01e1..30e16fa4b2e04c01c91fc4ce8044510b6f0e2507 100644
--- a/chrome/browser/ui/cocoa/task_manager_mac.mm
+++ b/chrome/browser/ui/cocoa/task_manager_mac.mm
@@ -9,6 +9,7 @@
 #include <algorithm>
 #include <vector>
 
+#include "base/command_line.h"
 #include "base/mac/bundle_locations.h"
 #include "base/macros.h"
 #include "base/strings/sys_string_conversions.h"
@@ -19,6 +20,7 @@
 #include "chrome/browser/ui/browser_dialogs.h"
 #import "chrome/browser/ui/cocoa/window_size_autosaver.h"
 #include "chrome/browser/ui/task_manager/task_manager_columns.h"
+#include "chrome/common/chrome_switches.h"

[tapted, 2017/03/02 22:44:39]

I think base/feature_list.h is the shiny new way to do all this. Pretty sure
then the changes are wholly contained in task_manager_mac.mm, plus we get
easy/automatic Finch integration if we want that, and a nicer avenue to add a
chrome://flag (if we want that).

The downside is just a little less convenience on the command line (i.e.
--enable_features=..).

Actually, I think we want the chrome://flag entry too -- wdyt?

[shrike, 2017/03/02 23:58:05]

We do need a chrome://flag entry. I look at MacViews/Harmony changes in Canary
and don't generally run it from the command line.

[tapted, 2017/03/07 22:52:26]

Per ^^^, is there a reason to not want to use base::FeatureList?

 #include "chrome/common/pref_names.h"
 #include "chrome/grit/generated_resources.h"
 #include "components/prefs/pref_service.h"
@@ -35,6 +37,11 @@
   return [NSString stringWithFormat:@"%d", id];
 }
 
+bool ShouldUseViewsTaskManager() {
+  return base::CommandLine::ForCurrentProcess()->HasSwitch(
+      switches::kUseViewsTaskManager);
+}
+
 }  // namespace
 
 @interface TaskManagerWindowController (Private)
@@ -639,10 +646,14 @@ - (NSButton*)endProcessButtonForTesting {
 
 // Declared in browser_dialogs.h.
 task_manager::TaskManagerTableModel* ShowTaskManager(Browser* browser) {
+  if (ShouldUseViewsTaskManager())
+    return chrome::ShowTaskManagerViews(browser);
   return task_manager::TaskManagerMac::Show();
 }
 
 void HideTaskManager() {
+  if (ShouldUseViewsTaskManager())
+    return chrome::HideTaskManagerViews();
   task_manager::TaskManagerMac::Hide();
 }