Adds ash::MaterialDesignController

ash/material_design/material_design_controller.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 <string>
+
+#include "ash/ash_switches.h"
+#include "ash/material_design/material_design_controller.h"
+#include "base/command_line.h"
+#include "base/logging.h"
+#include "base/trace_event/trace_event.h"
+
+namespace ash {
+
+namespace {
+MaterialDesignController::Mode mode_ =
+    MaterialDesignController::Mode::UNINITIALIZED;
+}  // namespace
+
+// static
+void MaterialDesignController::Initialize() {
+  TRACE_EVENT0("startup", "ash::MaterialDesignController::InitializeMode");
+  CHECK_EQ(Mode::UNINITIALIZED, mode_);

[oshima, 2016/04/27 22:26:22]

nit: DCHECK_EQ (sorry if I typed this)

[varkha, 2016/04/27 22:30:05]

I actually wanted this to assert in release builds so we never have this promise
broken. This is how it is for the top-chrome-md flag as well.

[oshima, 2016/04/27 22:58:44]

CHECK is for security/privacy issue, or you need data from fiels. If this ever
fails, then a user won't be able to start chrome, which is really bad. 

Bots are compiled with DCHECK_ALWAYS_ON, so you still should be able catch on
these builds.

[varkha, 2016/04/27 23:10:31]

Done.

+
+  const std::string switch_value =
+      base::CommandLine::ForCurrentProcess()->GetSwitchValueASCII(
+          ash::switches::kAshMaterialDesign);
+
+  if (switch_value == ash::switches::kAshMaterialDesignExperimental) {
+    SetMode(Mode::MATERIAL_EXPERIMENTAL);
+  } else if (switch_value == ash::switches::kAshMaterialDesignEnabled) {
+    SetMode(Mode::MATERIAL_NORMAL);
+  } else if (switch_value == ash::switches::kAshMaterialDesignDisabled) {
+    SetMode(Mode::NON_MATERIAL);
+  } else {
+    if (!switch_value.empty()) {
+      LOG(ERROR) << "Invalid value='" << switch_value
+                 << "' for command line switch '"
+                 << ash::switches::kAshMaterialDesign << "'.";
+    }
+    SetMode(DefaultMode());
+  }
+}
+
+// static
+bool MaterialDesignController::IsMaterial() {
+  return IsMaterialExperimental() || mode_ == Mode::MATERIAL_NORMAL;
+}
+
+// static
+bool MaterialDesignController::IsMaterialExperimental() {
+  CHECK_NE(Mode::UNINITIALIZED, mode_);

[oshima, 2016/04/27 22:26:22]

nit: ditto.

[varkha, 2016/04/27 22:30:05]

Acknowledged.

+  return mode_ == Mode::MATERIAL_EXPERIMENTAL;
+}
+
+// static
+MaterialDesignController::Mode MaterialDesignController::mode() {
+  return mode_;
+}
+
+// static
+MaterialDesignController::Mode MaterialDesignController::DefaultMode() {
+  return Mode::NON_MATERIAL;
+}
+
+// static
+void MaterialDesignController::SetMode(Mode mode) {
+  mode_ = mode;
+}
+
+// static
+void MaterialDesignController::Uninitialize() {
+  mode_ = Mode::UNINITIALIZED;
+}
+
+}  // namespace ui