[ios] Adds BrandedImageProvider and its associated image resources.

ios/public/provider/chrome/browser/images/test_branded_image_provider.h

Index: ios/public/provider/chrome/browser/images/test_branded_image_provider.h
diff --git a/ios/public/provider/chrome/browser/images/test_branded_image_provider.h b/ios/public/provider/chrome/browser/images/test_branded_image_provider.h
new file mode 100644
index 0000000000000000000000000000000000000000..2f3e479a9efad588f8d1cf9fb2c544619fc0ba2a
--- /dev/null
+++ b/ios/public/provider/chrome/browser/images/test_branded_image_provider.h
@@ -0,0 +1,29 @@
+// 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.
+
+#ifndef IOS_PUBLIC_PROVIDER_CHROME_BROWSER_IMAGES_TEST_BRANDED_IMAGE_PROVIDER_H_
+#define IOS_PUBLIC_PROVIDER_CHROME_BROWSER_IMAGES_TEST_BRANDED_IMAGE_PROVIDER_H_
+
+#include "ios/public/provider/chrome/browser/images/branded_image_provider.h"
+
+class TestBrandedImageProvider : public BrandedImageProvider {
+ public:
+  TestBrandedImageProvider();
+  ~TestBrandedImageProvider() override;
+
+  // BrandedImageProvider.
+  UIImage* GetAccountsListActivityControlsImage() override;

[sdefresne, 2016/11/22 13:29:30]

Do you really need to override those? The implementation appears to be the same
(return nil/false) as the super class.

[rohitrao (ping after 24h), 2016/11/22 13:33:47]

This test provider has no subclass-specific behavior at all.  Every method
returns nil or false.

Should I just remove this class entirely and use an instance of the superclass
instead?  Is there value in having this shell, or should we only add it if/when
we need it in the future?

I've added a number of other mostly-empty test providers.  Should I delete the
ones that do nothing?  Should I remove method overrides if they do the same
thing as the superclass implementation?

[sdefresne, 2016/11/22 13:41:27]

I'd prefer to keep this class as having a sub-class TestBrandedImageProvider
gives the tiny benefit that when/if we want to have a different implementation
for the tests than the default, we do not have to hunt for all the usages of the
base class in the tests.
I think we should remove overrides that are identical to super-class but keep
the classes for the same reason.

[rohitrao (ping after 24h), 2016/11/22 13:43:02]

SG.  I'll update this CL and fix up the other test providers in a followup.

+  UIImage* GetClearBrowsingDataAccountActivityImage() override;
+  UIImage* GetClearBrowsingDataSiteDataImage() override;
+  UIImage* GetContextualSearchHeaderImage() override;
+  UIImage* GetSigninConfirmationSyncSettingsImage() override;
+  UIImage* GetSigninConfirmationPersonalizeServicesImage() override;
+  bool GetToolbarVoiceSearchButtonImageId(int* image_id) override;
+  UIImage* GetWhatsNewIconImage(WhatsNewIcon type) override;
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(TestBrandedImageProvider);
+};
+
+#endif  // IOS_PUBLIC_PROVIDER_CHROME_BROWSER_IMAGES_TEST_BRANDED_IMAGE_PROVIDER_H_