Add flag to launch two displays for mus+ash.

services/ui/display/platform_screen_impl_ozone.cc

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "services/ui/display/platform_screen_impl_ozone.h"
 
+#include "base/command_line.h"
 #include "base/memory/ptr_util.h"
 #include "base/sys_info.h"
 #include "base/threading/thread_task_runner_handle.h"
 #include "third_party/skia/include/core/SkColor.h"
 #include "ui/display/types/display_constants.h"
 #include "ui/display/types/display_snapshot.h"
 #include "ui/display/types/native_display_delegate.h"
 #include "ui/gfx/geometry/rect.h"
 #include "ui/ozone/public/ozone_platform.h"
 
 namespace ui {
 
 namespace display {
 namespace {
 
 // TODO(rjkroege): Remove this code once ozone headless has the same
 // display creation semantics as ozone drm.
 // Some ozone platforms do not configure physical displays and so do not
 // callback into this class via the implementation of NativeDisplayObserver.
 // FixedSizeScreenConfiguration() short-circuits the implementation of display
 // configuration in this case by calling the |callback| provided to
 // ConfigurePhysicalDisplay() with a hard-coded |id| and |bounds|.
 void FixedSizeScreenConfiguration(
     const PlatformScreen::ConfiguredDisplayCallback& callback) {
-  callback.Run(1, gfx::Rect(1024, 768));
+  if (base::CommandLine::ForCurrentProcess()->HasSwitch("multi-display")) {
+    // This really doesn't work properly. Use at your own risk.
+    callback.Run(100, gfx::Rect(800, 800));
+    callback.Run(200, gfx::Rect(800, 0, 800, 800));
+  } else {
+    callback.Run(100, gfx::Rect(0, 0, 1024, 768));
+  }
 }
 
 // Needed for DisplayConfigurator::ForceInitialConfigure.
 const SkColor kChromeOsBootColor = SkColorSetRGB(0xfe, 0xfe, 0xfe);
 
 }  // namespace
 
 // static
 std::unique_ptr<PlatformScreen> PlatformScreen::Create() {
   return base::MakeUnique<PlatformScreenImplOzone>();
@@ skipping 18 matching lines @@
     display_configurator_.ForceInitialConfigure(kChromeOsBootColor);
   } else {
     // PostTask()ed to maximize control flow similarity with the ChromeOS case.
     base::ThreadTaskRunnerHandle::Get()->PostTask(
         FROM_HERE, base::Bind(&FixedSizeScreenConfiguration, callback));
   }
 }
 
 void PlatformScreenImplOzone::OnDisplayModeChanged(
     const ui::DisplayConfigurator::DisplayStateList& displays) {
-  // TODO(kylechar): Remove checks when multiple display support is added.
-  CHECK(displays.size() == 1) << "Mus only supports one 1 display";
+  // TODO(kylechar): Remove check when adding/removing displays is supported.
   CHECK(!callback_.is_null());
 
+  if (displays.size() > 1) {
+    LOG(ERROR)
+        << "Mus doesn't really support multiple displays, expect it to crash";
+  }
+
   gfx::Point origin;
   for (auto* display : displays) {
     const ui::DisplayMode* current_mode = display->current_mode();
     gfx::Rect bounds(origin, current_mode->size());
 
     callback_.Run(display->display_id(), bounds);
 
     // Move the origin so that next display is to the right of current display.
     origin.Offset(current_mode->size().width(), 0);
   }
 
   callback_.Reset();
 }
 
 void PlatformScreenImplOzone::OnDisplayModeChangeFailed(
     const ui::DisplayConfigurator::DisplayStateList& displays,
     MultipleDisplayState failed_new_state) {
   LOG(ERROR) << "OnDisplayModeChangeFailed from DisplayConfigurator";
   callback_.Reset();
 }
 
 }  // namespace display
 }  // namespace ui