Introduce new flag to control usage of MD in secondary (not top-chrome)

ui/base/material_design/material_design_controller.h

 // Copyright 2015 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.
 
 #ifndef UI_BASE_MATERIAL_DESIGN_MATERIAL_DESIGN_CONTROLLER_H_
 #define UI_BASE_MATERIAL_DESIGN_MATERIAL_DESIGN_CONTROLLER_H_
 
 #include "base/macros.h"
 #include "ui/base/ui_base_export.h"
 
@@ skipping 10 matching lines @@
   // updating references as these are used as array indices.
   enum Mode {
     // Classic, non-material design.
     NON_MATERIAL = 0,
     // Basic material design.
     MATERIAL_NORMAL = 1,
     // Material design targeted at mouse/touch hybrid devices.
     MATERIAL_HYBRID = 2
   };
 
+  // The extent to which the mode applies.
+  enum Extent {
+    // Only apply the Material Design modes to primary UI (toolbar, etc.).
+    PRIMARY = 0,
+    // Apply the Material Design modes to secondary UI (bubble contents, etc.).
+    SECONDARY = 1,
+  };
+
   // Initializes |mode_|. Must be called before checking |mode_|.
   static void Initialize();
 
   // Get the current Mode that should be used by the system.
   static Mode GetMode();
 
   // Returns true if the current mode is a material design variant.
   static bool IsModeMaterial();
 
+  // Returns true if the current mode is a material design variant and this mode
+  // should be extended to cover secondary UI.
+  static bool IsSecondaryUiMaterial();
+
   // Returns the per-platform default material design variant.
   static Mode DefaultMode();
 
  private:
   friend class test::MaterialDesignControllerTestAPI;
 
   // Tracks whether |mode_| has been initialized. This is necessary so tests can
   // reset the state back to a clean state during tear down.
   static bool is_mode_initialized_;
 
   // The current Mode to be used by the system.
   static Mode mode_;
 
+  // The extent to apply |mode_|.
+  static Extent extent_;

[varkha, 2016/04/27 23:06:05]

You would probably want to save / restore the mode here:
https://code.google.com/p/chromium/codesearch#chromium/src/ui/base/test/mater...

This is used to ensure that the tests do not change global state when a shard
runs multiple tests.

[Evan Stade, 2016/04/27 23:20:40]

I think this would make sense as soon as we decide we need a test that changes
|extent_|.

[varkha, 2016/04/27 23:30:58]

True but easy to forget and the results may be flaky rather than just failures.
I think it is easier to keep this atomic.

+
   // Declarations only. Do not allow construction of an object.
   MaterialDesignController();
   ~MaterialDesignController();
 
   // Resets the initialization state to uninitialized. To be used by tests to
   // allow calling Initialize() more than once.
   static void Uninitialize();
 
   // Set |mode_| to |mode| and updates |is_mode_initialized_| to true. Can be
   // used by tests to directly set the mode.
   static void SetMode(Mode mode);
 
   DISALLOW_COPY_AND_ASSIGN(MaterialDesignController);
 };
 
 }  // namespace ui
 
 #endif  // UI_BASE_MATERIAL_DESIGN_MATERIAL_DESIGN_CONTROLLER_H_