Enable MD by default on Windows for Canary/Dev and local builds.

ui/base/material_design/material_design_controller.cc

Index: ui/base/material_design/material_design_controller.cc
diff --git a/ui/base/material_design/material_design_controller.cc b/ui/base/material_design/material_design_controller.cc
index ddf60ed546e94909ac1ae96fa91d61358b2273b7..3e0388ec84952a1feb2b9c8fd48b142e84d2bf94 100644
--- a/ui/base/material_design/material_design_controller.cc
+++ b/ui/base/material_design/material_design_controller.cc
@@ -6,6 +6,7 @@
 
 #include "base/command_line.h"
 #include "base/logging.h"
+#include "base/metrics/field_trial.h"
 #include "base/trace_event/trace_event.h"
 #include "ui/base/material_design/material_design_controller.h"
 #include "ui/base/ui_base_switches.h"
@@ -25,8 +26,9 @@
 
 namespace ui {
 
+// static
 bool MaterialDesignController::is_mode_initialized_ = false;
-
+bool MaterialDesignController::windows_should_default_to_material_ = false;
 MaterialDesignController::Mode MaterialDesignController::mode_ =
     MaterialDesignController::NON_MATERIAL;
 
@@ -81,6 +83,21 @@ bool MaterialDesignController::IsSecondaryUiMaterial() {
 
 // static
 MaterialDesignController::Mode MaterialDesignController::DefaultMode() {
+  // The field trial value, if any, overrides the platform defaults below.
+  constexpr char kMaterialDesignModeFieldTrialName[] = "MaterialDesignMode";
+  constexpr char kNonMaterialGroupName[] = "NonMaterial";
+  constexpr char kMaterialNormalGroupName[] = "MaterialNormal";
+  constexpr char kMaterialHybridGroupName[] = "MaterialHybrid";
+  const std::string group =
+      base::FieldTrialList::FindFullName(kMaterialDesignModeFieldTrialName);
+  if (group == kNonMaterialGroupName)
+    return NON_MATERIAL;
+  if (group == kMaterialNormalGroupName)
+    return MATERIAL_NORMAL;
+  if (group == kMaterialHybridGroupName)
+    return MATERIAL_HYBRID;
+
+  // No recognized field trial group; fall back to per-platform defaults.
 #if defined(OS_CHROMEOS)
   if (DeviceDataManager::HasInstance() &&
       DeviceDataManager::GetInstance()->device_lists_complete()) {
@@ -109,12 +126,20 @@ MaterialDesignController::Mode MaterialDesignController::DefaultMode() {
   return MATERIAL_NORMAL;
 #elif defined(OS_LINUX)
   return MATERIAL_NORMAL;
+#elif defined(OS_WIN)
+  return windows_should_default_to_material_ ? MATERIAL_NORMAL : NON_MATERIAL;
 #else
   return NON_MATERIAL;
 #endif  // defined(OS_CHROMEOS)
 }
 
 // static
+void MaterialDesignController::SetWindowsShouldDefaultToMaterial(
+    bool default_to_material) {
+  windows_should_default_to_material_ = default_to_material;
+}
+
+// static
 void MaterialDesignController::Uninitialize() {
   is_mode_initialized_ = false;
 }