Remove Per-Monitor DPI Switches

This has been on by default for quite a few releases.
It's time to remove the switches.

BUG=426656,625289

Change-Id: I25bf2f3ec3d23cf51df6aeb5a1966a168b8617ad
Reviewed-on: https://chromium-review.googlesource.com/519564Reviewed-by: Scott Graham <scottmg@chromium.org>
Reviewed-by: Lei Zhang <thestig@chromium.org>
Commit-Queue: Robert Liao <robliao@chromium.org>
Cr-Commit-Position: refs/heads/master@{#476367}

chrome/app/chrome_exe_main_win.cc

@@ -123,14 +123,9 @@ void EnableHighDPISupport() {
   // does not have EnableChildWindowDpiMessage, necessary for correct non-client
   // area scaling across monitors.
   bool allowed_platform = base::win::GetVersion() >= base::win::VERSION_WIN10;
-  const base::CommandLine* command_line =
-      base::CommandLine::ForCurrentProcess();
-  bool per_monitor_dpi_switch =
-      !command_line->HasSwitch(switches::kDisablePerMonitorDpi);
   PROCESS_DPI_AWARENESS process_dpi_awareness =
-      allowed_platform && per_monitor_dpi_switch
-          ? PROCESS_PER_MONITOR_DPI_AWARE
-          : PROCESS_SYSTEM_DPI_AWARE;
+      allowed_platform ? PROCESS_PER_MONITOR_DPI_AWARE
+                       : PROCESS_SYSTEM_DPI_AWARE;
   if (!SetProcessDpiAwarenessWrapper(process_dpi_awareness)) {
     SetProcessDPIAwareWrapper();
   }

chrome/common/chrome_switches.cc

@@ -1056,16 +1056,9 @@ const char kMakeChromeDefault[] = "make-chrome-default";
 #endif  // defined(OS_MACOSX)
 
 #if defined(OS_WIN)
-// Disables per monitor DPI for supported Windows versions.
-// This flag overrides kEnablePerMonitorDpi.
-const char kDisablePerMonitorDpi[]          = "disable-per-monitor-dpi";
-
 // Fallback to XPS. By default connector uses CDD.
 const char kEnableCloudPrintXps[]           = "enable-cloud-print-xps";
 
-// Enables per monitor DPI for supported Windows versions.
-const char kEnablePerMonitorDpi[]           = "enable-per-monitor-dpi";
-
 // Force-enables the profile shortcut manager. This is needed for tests since
 // they use a custom-user-data-dir which disables this.
 const char kEnableProfileShortcutManager[]  = "enable-profile-shortcut-manager";

chrome/common/chrome_switches.h

@@ -314,9 +314,7 @@ extern const char kMakeChromeDefault[];
 #endif  // defined(OS_MACOSX)
 
 #if defined(OS_WIN)
-extern const char kDisablePerMonitorDpi[];
 extern const char kEnableCloudPrintXps[];
-extern const char kEnablePerMonitorDpi[];
 extern const char kEnableProfileShortcutManager[];
 extern const char kHideIcons[];
 extern const char kNoNetworkProfileWarning[];