Use browser top chrome material design by default on Chrome OS

Change the default value of the --top-chrome-md
flag to map to 'material' on Chrome OS, and
remain as 'non-material' on all other platforms.

On Chrome OS this will impact the assets, layout,
theming, and visual feedback of mouse/touch
interactions across the browser's UI surfaces,
namely:

* Tabstrip
* Toolbar
* Bookmarks bar
* Omnibox dropdown
* Incognito mode
* Bubbles
* Infobars

This CL does NOT make any changes to UI on other
platforms or non-browser UI on Chrome OS (shelf,
tray, etc). Furthermore, this CL should not
introduce any regressions in functionality.

Please use the label
Proj-MaterialDesign-NativeUI when filing bugs
in crbug.

BUG=581143,575270
TEST=MaterialDesignControllerTest.*

Review URL: https://codereview.chromium.org/1633733004

Cr-Commit-Position: refs/heads/master@{#371609}

chrome/browser/about_flags.cc

@@ -376,13 +376,17 @@ const FeatureEntry::Choice kFillOnAccountSelectChoices[] = {
 
 #if defined(ENABLE_TOPCHROME_MD)
 const FeatureEntry::Choice kTopChromeMaterialDesignChoices[] = {
-    {IDS_FLAGS_TOP_CHROME_MD_NON_MATERIAL, "", ""},
-    {IDS_FLAGS_TOP_CHROME_MD_MATERIAL,
+  { IDS_GENERIC_EXPERIMENT_CHOICE_DEFAULT, "", "" },
+  { IDS_FLAGS_TOP_CHROME_MD_NON_MATERIAL,
+    switches::kTopChromeMD,
+    switches::kTopChromeMDNonMaterial },
+  { IDS_FLAGS_TOP_CHROME_MD_MATERIAL,
     switches::kTopChromeMD,
-     switches::kTopChromeMDMaterial},
-    {IDS_FLAGS_TOP_CHROME_MD_MATERIAL_HYBRID,
+    switches::kTopChromeMDMaterial },
+  { IDS_FLAGS_TOP_CHROME_MD_MATERIAL_HYBRID,
     switches::kTopChromeMD,
-     switches::kTopChromeMDMaterialHybrid}};
+    switches::kTopChromeMDMaterialHybrid },
+};
 #endif
 
 #if defined(OS_CHROMEOS)

ui/base/material_design/material_design_controller.cc

@@ -28,6 +28,14 @@ bool MaterialDesignController::IsModeMaterial() {
          GetMode() == Mode::MATERIAL_HYBRID;
 }
 
+MaterialDesignController::Mode MaterialDesignController::DefaultMode() {
+#if defined(OS_CHROMEOS)
+  return Mode::MATERIAL_NORMAL;
+#else
+  return Mode::NON_MATERIAL;
+#endif  // defined(OS_CHROMEOS)
+}
+
 void MaterialDesignController::InitializeMode() {
 #if !defined(ENABLE_TOPCHROME_MD)
   SetMode(Mode::NON_MATERIAL);
@@ -43,10 +51,12 @@ void MaterialDesignController::InitializeMode() {
   } else if (switch_value == switches::kTopChromeMDNonMaterial) {
     SetMode(Mode::NON_MATERIAL);
   } else {
+    if (!switch_value.empty()) {
       LOG(ERROR) << "Invalid value='" << switch_value
                  << "' for command line switch '" << switches::kTopChromeMD
                  << "'.";
-    SetMode(Mode::NON_MATERIAL);
+    }
+    SetMode(DefaultMode());
   }
 #endif  // !defined(ENABLE_TOPCHROME_MD)
 }

ui/base/material_design/material_design_controller.h

@@ -34,6 +34,9 @@ class UI_BASE_EXPORT MaterialDesignController {
   // Returns true if the current mode is a material design variant.
   static bool IsModeMaterial();
 
+  // Returns the per-platform default material design variant.
+  static Mode DefaultMode();
+
  private:
   friend class test::MaterialDesignControllerTestAPI;
 

ui/base/material_design/material_design_controller_unittest.cc

@@ -77,33 +77,33 @@ TEST_F(
             MaterialDesignController::GetMode());
 }
 
-// Verify command line value "" maps to Mode::NON_MATERIAL when the compile time
+// Verify command line value "" maps to the default mode when the compile time
 // flag is defined.
 TEST_F(
     MaterialDesignControllerTest,
     DisabledCommandLineValueMapsToNonMaterialModeWhenCompileTimeFlagEnabled) {
   base::CommandLine::ForCurrentProcess()->AppendSwitchASCII(
       switches::kTopChromeMD, "");
-  EXPECT_EQ(MaterialDesignController::Mode::NON_MATERIAL,
+  EXPECT_EQ(MaterialDesignController::DefaultMode(),
             MaterialDesignController::GetMode());
 }
 
-// Verify no command line value maps to Mode::NON_MATERIAL when the compile time
+// Verify the current mode is reported as the default mode when no command line
 // flag is defined.
 TEST_F(MaterialDesignControllerTest,
        NoCommandLineValueMapsToNonMaterialModeWhenCompileTimeFlagEnabled) {
   ASSERT_FALSE(base::CommandLine::ForCurrentProcess()->HasSwitch(
       switches::kTopChromeMD));
-  EXPECT_EQ(MaterialDesignController::Mode::NON_MATERIAL,
+  EXPECT_EQ(MaterialDesignController::DefaultMode(),
             MaterialDesignController::GetMode());
 }
 
-// Verify an invalid command line value uses the default NON_MATERIAL mode.
+// Verify an invalid command line value uses the default mode.
 TEST_F(MaterialDesignControllerTest, InvalidCommandLineValue) {
   const std::string kInvalidValue = "1nvalid-valu3";
   base::CommandLine::ForCurrentProcess()->AppendSwitchASCII(
       switches::kTopChromeMD, kInvalidValue);
-  EXPECT_EQ(MaterialDesignController::Mode::NON_MATERIAL,
+  EXPECT_EQ(MaterialDesignController::DefaultMode(),
             MaterialDesignController::GetMode());
 }
 

ui/base/ui_base_switches.cc

@@ -79,7 +79,7 @@ const char kTopChromeMDMaterial[] = "material";
 const char kTopChromeMDMaterialHybrid[] = "material-hybrid";
 
 // Classic, non-material, mode for the |kTopChromeMD| switch.
-const char kTopChromeMDNonMaterial[] = "";
+const char kTopChromeMDNonMaterial[] = "non-material";
 #endif  // defined(ENABLE_TOPCHROME_MD)
 
 // On Windows only: requests that Chrome connect to the running Metro viewer