Remove the enable_task_manager build flag and define.

chrome/browser/ui/browser_commands.cc

Index: chrome/browser/ui/browser_commands.cc
diff --git a/chrome/browser/ui/browser_commands.cc b/chrome/browser/ui/browser_commands.cc
index d0066faf760efc4aaa917cd6b7becb1baf9fff6e..6f8d4a9f666aa97cfb3eeddd6bf816552724b0f4 100644
--- a/chrome/browser/ui/browser_commands.cc
+++ b/chrome/browser/ui/browser_commands.cc
@@ -1082,7 +1082,7 @@ void ToggleDevToolsWindow(Browser* browser, DevToolsToggleAction action) {
 }
 
 bool CanOpenTaskManager() {
-#if defined(ENABLE_TASK_MANAGER)
+#if !defined(OS_ANDROID)
   return true;
 #else
   return false;
@@ -1090,7 +1090,7 @@ bool CanOpenTaskManager() {
 }
 
 void OpenTaskManager(Browser* browser) {
-#if defined(ENABLE_TASK_MANAGER)
+#if !defined(OS_ANDROID)
   content::RecordAction(UserMetricsAction("TaskManager"));
   chrome::ShowTaskManager(browser);
 #else