Move storage quota unit tests and test doubles next to the files they cover.

content/test/BUILD.gn

Index: content/test/BUILD.gn
diff --git a/content/test/BUILD.gn b/content/test/BUILD.gn
index 58969065285dc134bb9d022fe3a74393b6a243b8..3a5b9ab2e70526302d1feae365713d6feeb6e4a1 100644
--- a/content/test/BUILD.gn
+++ b/content/test/BUILD.gn
@@ -86,8 +86,6 @@ static_library("test_support") {
     "../public/test/mock_render_thread.h",
     "../public/test/mock_resource_context.cc",
     "../public/test/mock_resource_context.h",
-    "../public/test/mock_storage_client.cc",
-    "../public/test/mock_storage_client.h",
     "../public/test/navigation_simulator.cc",
     "../public/test/navigation_simulator.h",
     "../public/test/ppapi_test_utils.cc",
@@ -1190,14 +1188,6 @@ test("content_unittests") {
     "../browser/payments/payment_app_provider_impl_unittest.cc",
     "../browser/payments/payment_manager_unittest.cc",
     "../browser/presentation/presentation_service_impl_unittest.cc",
-    "../browser/quota/mock_quota_manager.cc",
-    "../browser/quota/mock_quota_manager.h",
-    "../browser/quota/mock_quota_manager_proxy.cc",
-    "../browser/quota/mock_quota_manager_proxy.h",
-    "../browser/quota/mock_quota_manager_unittest.cc",
-    "../browser/quota/quota_manager_unittest.cc",
-    "../browser/quota/quota_temporary_storage_evictor_unittest.cc",
-    "../browser/quota/storage_monitor_unittest.cc",
     "../browser/renderer_host/clipboard_message_filter_unittest.cc",
     "../browser/renderer_host/compositor_resize_lock_unittest.cc",
     "../browser/renderer_host/dwrite_font_proxy_message_filter_win_unittest.cc",