[Media Router] Factor extension-related logic out of MediaRouterMojoImpl

chrome/browser/media/router/event_page_request_manager.cc

Index: chrome/browser/media/router/event_page_request_manager.cc
diff --git a/chrome/browser/media/router/event_page_request_manager.cc b/chrome/browser/media/router/event_page_request_manager.cc
new file mode 100644
index 0000000000000000000000000000000000000000..7b0b3cf034d6032e9a6a362db84c49783bf47024
--- /dev/null
+++ b/chrome/browser/media/router/event_page_request_manager.cc
@@ -0,0 +1,155 @@
+// Copyright 2017 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/media/router/event_page_request_manager.h"
+
+#include "base/bind.h"
+#include "base/logging.h"
+#include "base/macros.h"
+#include "chrome/browser/media/router/mojo/media_router_mojo_metrics.h"
+#include "extensions/browser/event_page_tracker.h"
+#include "extensions/browser/process_manager.h"
+#include "extensions/browser/process_manager_factory.h"
+
+namespace media_router {
+
+EventPageRequestManager::~EventPageRequestManager() = default;
+
+void EventPageRequestManager::Shutdown() {
+  event_page_tracker_ = nullptr;
+}
+
+void EventPageRequestManager::SetWakeReason(
+    MediaRouteProviderWakeReason reason) {
+  DCHECK(reason != MediaRouteProviderWakeReason::TOTAL_COUNT);
+  if (current_wake_reason_ == MediaRouteProviderWakeReason::TOTAL_COUNT)
+    current_wake_reason_ = reason;
+}
+
+void EventPageRequestManager::SetExtensionId(const std::string& extension_id) {
+  media_route_provider_extension_id_ = extension_id;
+}
+
+void EventPageRequestManager::RunOrDefer(base::OnceClosure request) {
+  if (mojo_connections_ready_) {
+    DCHECK(!media_route_provider_extension_id_.empty());
+    std::move(request).Run();
+  } else {
+    EnqueueRequest(std::move(request));
+    if (IsEventPageSuspended())
+      AttemptWakeEventPage();
+  }
+}
+
+void EventPageRequestManager::OnMojoConnectionsReady() {
+  if (IsEventPageSuspended()) {
+    DVLOG(1)
+        << "OnMojoConnectionsReady was called while extension is suspended.";
+    SetWakeReason(MediaRouteProviderWakeReason::REGISTER_MEDIA_ROUTE_PROVIDER);
+    AttemptWakeEventPage();
+    return;
+  }
+
+  mojo_connections_ready_ = true;
+  for (auto& next_request : pending_requests_)
+    std::move(next_request).Run();
+  pending_requests_.clear();
+  wakeup_attempt_count_ = 0;
+}
+
+void EventPageRequestManager::OnMojoConnectionError() {
+  mojo_connections_ready_ = false;
+
+  // If this method is invoked while there are pending requests, then
+  // it means we tried to wake the extension, but weren't able to complete the
+  // connection to media route provider. Since we do not know whether the error
+  // is transient, reattempt the wakeup.
+  if (!pending_requests_.empty()) {
+    DLOG(ERROR) << "A connection error while there are pending requests.";
+    SetWakeReason(MediaRouteProviderWakeReason::CONNECTION_ERROR);
+    AttemptWakeEventPage();
+  }
+}
+
+EventPageRequestManager::EventPageRequestManager(
+    content::BrowserContext* context)
+    : event_page_tracker_(extensions::ProcessManager::Get(context)),
+      current_wake_reason_(MediaRouteProviderWakeReason::TOTAL_COUNT),
+      weak_factory_(this) {}
+
+void EventPageRequestManager::EnqueueRequest(base::OnceClosure closure) {

[imcheng, 2017/06/30 00:17:38]

s/closure/request for consistency.

[takumif, 2017/07/01 01:16:44]

Done.

+  pending_requests_.push_back(std::move(closure));
+  if (pending_requests_.size() > kMaxPendingRequests) {
+    DLOG(ERROR) << "Reached max queue size. Dropping oldest request.";
+    pending_requests_.pop_front();
+  }
+  DVLOG(2) << "EnqueueRequest (queue-length=" << pending_requests_.size()
+           << ")";
+}
+
+void EventPageRequestManager::DrainPendingRequests() {
+  DLOG(ERROR) << "Draining request queue. (queue-length="
+              << pending_requests_.size() << ")";
+  pending_requests_.clear();
+}
+
+bool EventPageRequestManager::IsEventPageSuspended() {
+  return !event_page_tracker_ || event_page_tracker_->IsEventPageSuspended(
+                                     media_route_provider_extension_id_);
+}
+
+void EventPageRequestManager::AttemptWakeEventPage() {
+  ++wakeup_attempt_count_;
+  if (wakeup_attempt_count_ > kMaxWakeupAttemptCount) {
+    DLOG(ERROR) << "Attempted too many times to wake up event page.";
+    DrainPendingRequests();
+    wakeup_attempt_count_ = 0;
+    MediaRouterMojoMetrics::RecordMediaRouteProviderWakeup(
+        MediaRouteProviderWakeup::ERROR_TOO_MANY_RETRIES);
+    return;
+  }
+
+  DVLOG(1) << "Attempting to wake up event page: attempt "
+           << wakeup_attempt_count_;
+  if (!event_page_tracker_) {
+    DLOG(ERROR) << "Attempted to wake up event page without a valid event page"
+                   "tracker";
+    return;
+  }
+
+  // This return false if the extension is already awake.
+  // Callback is bound using WeakPtr because |event_page_tracker_| outlives
+  // |this|.
+  if (!event_page_tracker_->WakeEventPage(
+          media_route_provider_extension_id_,
+          base::Bind(&EventPageRequestManager::OnWakeComplete,
+                     weak_factory_.GetWeakPtr()))) {
+    DLOG(ERROR) << "Failed to schedule a wakeup for event page.";
+  }
+}
+
+void EventPageRequestManager::OnWakeComplete(bool success) {
+  if (success) {
+    MediaRouterMojoMetrics::RecordMediaRouteProviderWakeReason(
+        current_wake_reason_);
+    ClearWakeReason();
+    MediaRouterMojoMetrics::RecordMediaRouteProviderWakeup(
+        MediaRouteProviderWakeup::SUCCESS);
+    return;
+  }
+
+  // This is likely an non-retriable error. Drop the pending requests.
+  DLOG(ERROR) << "An error encountered while waking the event page.";
+  ClearWakeReason();
+  DrainPendingRequests();
+  MediaRouterMojoMetrics::RecordMediaRouteProviderWakeup(
+      MediaRouteProviderWakeup::ERROR_UNKNOWN);
+}
+
+void EventPageRequestManager::ClearWakeReason() {
+  DCHECK(current_wake_reason_ != MediaRouteProviderWakeReason::TOTAL_COUNT);
+  current_wake_reason_ = MediaRouteProviderWakeReason::TOTAL_COUNT;
+}
+
+}  // namespace media_router