arc: Disable Custom Tabs when SPM is disabled

BUG=955035
TEST=Manually verify that Custom Tabs is disabled when SPM is disabled

Change-Id: I64edf464a3ab54f83460395e1c85f8febdc10f93
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1580996
Commit-Queue: Yusuke Sato <yusukes@chromium.org>
Reviewed-by: Scott Violet <sky@chromium.org>
Reviewed-by: Yusuke Sato <yusukes@chromium.org>
Cr-Commit-Position: refs/heads/master@{#653647}

components/arc/DEPS

@@ -18,7 +18,7 @@ include_rules = [
   "+storage/browser/fileapi",
   "+third_party/re2",
   "+third_party/skia",
-  "+ui/base/ime",
+  "+ui/base",
   "+ui/gfx/geometry",
   "+ui/gfx/range/range.h",
 ]

components/arc/session/arc_session_impl.cc

@@ -37,6 +37,7 @@
 #include "mojo/public/cpp/platform/platform_handle.h"
 #include "mojo/public/cpp/platform/socket_utils_posix.h"
 #include "mojo/public/cpp/system/invitation.h"
+#include "ui/base/ui_base_features.h"
 
 namespace arc {
 
@@ -371,8 +372,9 @@ void ArcSessionImpl::OnLcdDensity(int32_t lcd_density) {
       base::FeatureList::IsEnabled(arc::kNativeBridgeExperimentFeature));
   request.set_arc_file_picker_experiment(
       base::FeatureList::IsEnabled(arc::kFilePickerExperimentFeature));
-  // Enable Custom Tabs only on Dev and Cannary.
+  // Enable Custom Tabs only on Dev and Cannary, and only when Mash is enabled.
   const bool is_custom_tab_enabled =
+      base::FeatureList::IsEnabled(features::kSingleProcessMash) &&
       base::FeatureList::IsEnabled(arc::kCustomTabsExperimentFeature) &&
       delegate_->GetChannel() != version_info::Channel::STABLE &&
       delegate_->GetChannel() != version_info::Channel::BETA;