[sms] Introduce a message handler and add a mapping in SharingService

Per instructions on the Unido design doc [1], this is the (2-4) step in
the process of creating a new Unido feature:

1) Add a new SharingMessage to the proto and update metrics mapping
2) Add your new SharingFCMHandler in SharingService constructor
3) Add a new feature in DeviceInfoSpecifics.EnabledFeatures
4) Add your enabled feature to SharingDeviceRegistration
5) Use SharingService to list device candidates, and use the new SendMessageToDevice to send messages

Step (1) is here:

https://chromium-review.googlesource.com/c/chromium/src/+/1867444

Steps (5) will follow in separate CLs, to ease reviewing and ease
other features tracking how to integrate.

Design Doc: https://docs.google.com/document/d/1da8CjO71DlFbBzDcSosFRXTvDsKII_XMCohpZLQ_QbM/edit?userstoinvite=himanshujaju%40google.com&ts=5da89bb1&actionButton=1

Bug: 1015645
Change-Id: Ia1ca925c107fb9ffe2e148ed0a82997268464657
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1867125Reviewed-by: Tim Schumann <tschumann@chromium.org>
Reviewed-by: Alex Chau <alexchau@chromium.org>
Commit-Queue: Sam Goto <goto@chromium.org>
Cr-Commit-Position: refs/heads/master@{#707958}

chrome/browser/BUILD.gn

@@ -2844,6 +2844,10 @@ jumbo_static_library("browser") {
       "search_engines/template_url_service_factory_android.h",
       "sharing/shared_clipboard/shared_clipboard_message_handler_android.cc",
       "sharing/shared_clipboard/shared_clipboard_message_handler_android.h",
+      "sharing/sms/sms_fetch_request_handler.cc",
+      "sharing/sms/sms_fetch_request_handler.h",
+      "sharing/sms/sms_flags.cc",
+      "sharing/sms/sms_flags.h",
       "signin/identity_services_provider_android.cc",
       "signin/signin_manager_android_factory.cc",
       "signin/signin_manager_android_factory.h",

chrome/browser/sharing/sharing_device_registration.cc

@@ -16,6 +16,7 @@
 #include "chrome/browser/sharing/sharing_constants.h"
 #include "chrome/browser/sharing/sharing_device_registration_result.h"
 #include "chrome/browser/sharing/sharing_sync_preference.h"
+#include "chrome/browser/sharing/sms/sms_flags.h"
 #include "chrome/browser/sharing/vapid_key_manager.h"
 #include "chrome/common/pref_names.h"
 #include "components/gcm_driver/crypto/p256_key_util.h"
@@ -199,6 +200,8 @@ SharingDeviceRegistration::GetEnabledFeatures() const {
     enabled_features.insert(SharingSpecificFields::CLICK_TO_CALL);
   if (IsSharedClipboardSupported())
     enabled_features.insert(SharingSpecificFields::SHARED_CLIPBOARD);
+  if (IsSmsFetcherSupported())
+    enabled_features.insert(SharingSpecificFields::SMS_FETCHER);
 
   return enabled_features;
 }
@@ -223,6 +226,14 @@ bool SharingDeviceRegistration::IsSharedClipboardSupported() const {
   return base::FeatureList::IsEnabled(kSharedClipboardReceiver);
 }
 
+bool SharingDeviceRegistration::IsSmsFetcherSupported() const {
+#if defined(OS_ANDROID)
+  return base::FeatureList::IsEnabled(kSmsFetchRequestHandler);
+#endif
+
+  return false;
+}
+
 void SharingDeviceRegistration::SetEnabledFeaturesForTesting(
     std::set<SharingSpecificFields::EnabledFeatures> enabled_features) {
   enabled_features_testing_value_ = std::move(enabled_features);

chrome/browser/sharing/sharing_device_registration.h

@@ -51,6 +51,9 @@ class SharingDeviceRegistration {
   // Returns if device can handle receiving of shared clipboard contents.
   virtual bool IsSharedClipboardSupported() const;
 
+  // Returns if device can handle receiving of sms fetcher requests.
+  virtual bool IsSmsFetcherSupported() const;
+
   // For testing
   void SetEnabledFeaturesForTesting(
       std::set<sync_pb::SharingSpecificFields_EnabledFeatures>

chrome/browser/sharing/sharing_service.cc

@@ -27,6 +27,7 @@
 #include "chrome/browser/sharing/sharing_message_handler.h"
 #include "chrome/browser/sharing/sharing_metrics.h"
 #include "chrome/browser/sharing/sharing_sync_preference.h"
+#include "chrome/browser/sharing/sms/sms_fetch_request_handler.h"
 #include "chrome/browser/sharing/vapid_key_manager.h"
 #include "chrome/grit/generated_resources.h"
 #include "components/gcm_driver/crypto/gcm_encryption_provider.h"
@@ -183,6 +184,13 @@ SharingService::SharingService(
         chrome_browser_sharing::SharingMessage::kClickToCallMessage,
         &click_to_call_message_handler_);
   }
+
+  if (sharing_device_registration_->IsSmsFetcherSupported()) {
+    sms_fetch_request_handler_ = std::make_unique<SmsFetchRequestHandler>();
+    fcm_handler_->AddSharingHandler(
+        chrome_browser_sharing::SharingMessage::kSmsFetchRequest,
+        sms_fetch_request_handler_.get());
+  }
 #endif  // defined(OS_ANDROID)
 
   if (sharing_device_registration_->IsSharedClipboardSupported()) {

chrome/browser/sharing/sharing_service.h

@@ -47,6 +47,7 @@ class SharedClipboardMessageHandler;
 class SharingFCMHandler;
 class SharingFCMSender;
 class SharingSyncPreference;
+class SmsFetchRequestHandler;
 class VapidKeyManager;
 enum class SharingDeviceRegistrationResult;
 
@@ -209,6 +210,7 @@ class SharingService : public KeyedService,
   AckMessageHandler ack_message_handler_;
 #if defined(OS_ANDROID)
   ClickToCallMessageHandler click_to_call_message_handler_;
+  std::unique_ptr<SmsFetchRequestHandler> sms_fetch_request_handler_;
 #endif  // defined(OS_ANDROID)
   std::unique_ptr<SharedClipboardMessageHandler>
       shared_clipboard_message_handler_;

chrome/browser/sharing/sms/sms_fetch_request_handler.cc

+// Copyright 2019 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.
+
+#include "chrome/browser/sharing/sms/sms_fetch_request_handler.h"
+
+#include "base/logging.h"
+#include "chrome/browser/sharing/proto/sms_fetch_request.pb.h"
+
+SmsFetchRequestHandler::SmsFetchRequestHandler() = default;
+
+SmsFetchRequestHandler::~SmsFetchRequestHandler() = default;
+
+void SmsFetchRequestHandler::OnMessage(
+    const chrome_browser_sharing::SharingMessage& message) {
+  DCHECK(message.has_sms_fetch_request());
+  // TODO(crbug.com/1015645): implementation left pending deliberately.
+  NOTIMPLEMENTED();
+}

chrome/browser/sharing/sms/sms_fetch_request_handler.h

+// Copyright 2019 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 CHROME_BROWSER_SHARING_SMS_SMS_FETCH_REQUEST_HANDLER_H_
+#define CHROME_BROWSER_SHARING_SMS_SMS_FETCH_REQUEST_HANDLER_H_
+
+#include "base/macros.h"
+#include "chrome/browser/sharing/proto/sharing_message.pb.h"
+#include "chrome/browser/sharing/sharing_message_handler.h"
+
+// Handles incoming messages for the sms fetcher feature.
+class SmsFetchRequestHandler : public SharingMessageHandler {
+ public:
+  SmsFetchRequestHandler();
+  ~SmsFetchRequestHandler() override;
+
+  // SharingMessageHandler
+  void OnMessage(
+      const chrome_browser_sharing::SharingMessage& message) override;
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(SmsFetchRequestHandler);
+};
+
+#endif  // CHROME_BROWSER_SHARING_SMS_SMS_FETCH_REQUEST_HANDLER_H_

chrome/browser/sharing/sms/sms_flags.cc

+// Copyright 2019 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.
+
+#include "chrome/browser/sharing/sms/sms_flags.h"
+
+const base::Feature kSmsFetchRequestHandler{"kSmsFetchRequestHandler",
+                                            base::FEATURE_DISABLED_BY_DEFAULT};

chrome/browser/sharing/sms/sms_flags.h

+// Copyright 2019 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 CHROME_BROWSER_SHARING_SMS_SMS_FLAGS_H_
+#define CHROME_BROWSER_SHARING_SMS_SMS_FLAGS_H_
+
+#include "base/feature_list.h"
+
+// Feature to allow devices to receive the sms fetch request.
+extern const base::Feature kSmsFetchRequestHandler;
+
+#endif  // CHROME_BROWSER_SHARING_SMS_SMS_FLAGS_H_

components/sync/protocol/device_info_specifics.proto

@@ -95,6 +95,7 @@ message SharingSpecificFields {
     UNKNOWN = 0;
     CLICK_TO_CALL = 1;
     SHARED_CLIPBOARD = 2;
+    SMS_FETCHER = 3;
   }
 
   // A list of enabled Sharing features.