Make Pepper use Mojo-based support for media-device enumeration and monitoring.

content/renderer/pepper/pepper_device_enumeration_host_helper.cc

 // Copyright (c) 2012 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 "content/renderer/pepper/pepper_device_enumeration_host_helper.h"
 
 #include "base/bind.h"
 #include "base/location.h"
 #include "base/logging.h"
 #include "base/macros.h"
 #include "base/memory/weak_ptr.h"
 #include "base/single_thread_task_runner.h"
 #include "base/threading/thread_task_runner_handle.h"
 #include "ipc/ipc_message.h"
 #include "ppapi/c/pp_errors.h"
 #include "ppapi/host/dispatch_host_message.h"
 #include "ppapi/host/host_message_context.h"
 #include "ppapi/host/ppapi_host.h"
 #include "ppapi/host/resource_host.h"
 #include "ppapi/proxy/ppapi_messages.h"
 #include "ppapi/shared_impl/ppb_device_ref_shared.h"
 
 using ppapi::host::HostMessageContext;
 
 namespace content {
 
 // Makes sure that StopEnumerateDevices() is called for each EnumerateDevices().
-class PepperDeviceEnumerationHostHelper::ScopedRequest
-    : public base::SupportsWeakPtr<ScopedRequest> {
+class PepperDeviceEnumerationHostHelper::ScopedEnumerationRequest
+    : public base::SupportsWeakPtr<ScopedEnumerationRequest> {
  public:
   // |owner| must outlive this object.
-  ScopedRequest(PepperDeviceEnumerationHostHelper* owner,
-                const Delegate::EnumerateDevicesCallback& callback)
+  ScopedEnumerationRequest(PepperDeviceEnumerationHostHelper* owner,
+                           const Delegate::DevicesCallback& callback)
       : owner_(owner),
         callback_(callback),
         requested_(false),
-        request_id_(0),
         sync_call_(false) {
     if (!owner_->document_url_.is_valid())
       return;
 
     requested_ = true;
 
     // Note that the callback passed into
     // PepperDeviceEnumerationHostHelper::Delegate::EnumerateDevices() may be
-    // called synchronously. In that case, |request_id_| hasn't been updated
-    // when the callback is called. Moreover, |callback| may destroy this
+    // called synchronously. In that case, |callback| may destroy this
     // object. So we don't pass in |callback| directly. Instead, we use
     // EnumerateDevicesCallbackBody() to ensure that we always call |callback|
     // asynchronously.
     sync_call_ = true;
     DCHECK(owner_->delegate_);
-    request_id_ = owner_->delegate_->EnumerateDevices(
-        owner_->device_type_,
-        owner_->document_url_,
-        base::Bind(&ScopedRequest::EnumerateDevicesCallbackBody, AsWeakPtr()));
+    owner_->delegate_->EnumerateDevices(
+        owner_->device_type_, owner_->document_url_,
+        base::Bind(&ScopedEnumerationRequest::EnumerateDevicesCallbackBody,
+                   AsWeakPtr()));
     sync_call_ = false;
   }
 
-  ~ScopedRequest() {
+  bool requested() const { return requested_; }
+
+ private:
+  void EnumerateDevicesCallbackBody(
+      const std::vector<ppapi::DeviceRefData>& devices) {
+    if (sync_call_) {
+      base::ThreadTaskRunnerHandle::Get()->PostTask(
+          FROM_HERE,
+          base::Bind(&ScopedEnumerationRequest::EnumerateDevicesCallbackBody,
+                     AsWeakPtr(), devices));
+    } else {
+      callback_.Run(devices);
+      // This object may have been destroyed at this point.
+    }
+  }
+
+  PepperDeviceEnumerationHostHelper* owner_;

[bbudge, 2016/11/10 18:38:55]

This isn't used outside of the constructor. Can we get rid of it?

[Guido Urdaneta, 2016/11/10 19:01:17]

Done.

+  PepperDeviceEnumerationHostHelper::Delegate::DevicesCallback callback_;
+  bool requested_;
+  bool sync_call_;
+
+  DISALLOW_COPY_AND_ASSIGN(ScopedEnumerationRequest);
+};
+
+// Makes sure that StopMonitoringDevices() is called for each
+// StartMonitoringDevices().
+class PepperDeviceEnumerationHostHelper::ScopedMonitoringRequest
+    : public base::SupportsWeakPtr<ScopedMonitoringRequest> {
+ public:
+  // |owner| must outlive this object.
+  ScopedMonitoringRequest(PepperDeviceEnumerationHostHelper* owner,
+                          const Delegate::DevicesCallback& callback)
+      : owner_(owner),
+        callback_(callback),
+        requested_(false),
+        subscription_id_(0) {
+    if (!owner_->document_url_.is_valid())
+      return;
+
+    requested_ = true;
+
+    DCHECK(owner_->delegate_);
+    // |callback| is never called synchronously by StartMonitoringDevices(),
+    // so it is OK to pass it directly, even if |callback| destroys |this|.
+    subscription_id_ = owner_->delegate_->StartMonitoringDevices(
+        owner_->device_type_, owner_->document_url_, callback);
+  }
+
+  ~ScopedMonitoringRequest() {
     if (requested_ && owner_->delegate_) {

[bbudge, 2016/11/10 18:38:54]

Maybe DCHECK(owner) here?

[Guido Urdaneta, 2016/11/10 19:01:17]

Added DCHECK in constructor and made the field const.

-      owner_->delegate_->StopEnumerateDevices(request_id_);
+      owner_->delegate_->StopMonitoringDevices(owner_->device_type_,
+                                               subscription_id_);
     }
   }
 
   bool requested() const { return requested_; }
 
  private:
-  void EnumerateDevicesCallbackBody(
-      int request_id,
-      const std::vector<ppapi::DeviceRefData>& devices) {
-    if (sync_call_) {
-      base::ThreadTaskRunnerHandle::Get()->PostTask(
-          FROM_HERE, base::Bind(&ScopedRequest::EnumerateDevicesCallbackBody,
-                                AsWeakPtr(), request_id, devices));
-    } else {
-      DCHECK_EQ(request_id_, request_id);
-      callback_.Run(request_id, devices);
-      // This object may have been destroyed at this point.
-    }
-  }
+  PepperDeviceEnumerationHostHelper* owner_;
+  PepperDeviceEnumerationHostHelper::Delegate::DevicesCallback callback_;
+  bool requested_;
+  int subscription_id_;
 
-  PepperDeviceEnumerationHostHelper* owner_;
-  PepperDeviceEnumerationHostHelper::Delegate::EnumerateDevicesCallback
-      callback_;
-  bool requested_;
-  int request_id_;
-  bool sync_call_;
-
-  DISALLOW_COPY_AND_ASSIGN(ScopedRequest);
+  DISALLOW_COPY_AND_ASSIGN(ScopedMonitoringRequest);
 };
 
 PepperDeviceEnumerationHostHelper::PepperDeviceEnumerationHostHelper(
     ppapi::host::ResourceHost* resource_host,
     base::WeakPtr<Delegate> delegate,
     PP_DeviceType_Dev device_type,
     const GURL& document_url)
     : resource_host_(resource_host),
       delegate_(delegate),
       device_type_(device_type),
@@ skipping 28 matching lines @@
 
   *handled = false;
   return PP_ERROR_FAILED;
 }
 
 int32_t PepperDeviceEnumerationHostHelper::OnEnumerateDevices(
     HostMessageContext* context) {
   if (enumerate_devices_context_.is_valid())
     return PP_ERROR_INPROGRESS;
 
-  enumerate_.reset(new ScopedRequest(
+  enumerate_.reset(new ScopedEnumerationRequest(
       this,
       base::Bind(&PepperDeviceEnumerationHostHelper::OnEnumerateDevicesComplete,
                  base::Unretained(this))));
   if (!enumerate_->requested())
     return PP_ERROR_FAILED;
 
   enumerate_devices_context_ = context->MakeReplyMessageContext();
   return PP_OK_COMPLETIONPENDING;
 }
 
 int32_t PepperDeviceEnumerationHostHelper::OnMonitorDeviceChange(
     HostMessageContext* /* context */,
     uint32_t callback_id) {
-  monitor_.reset(new ScopedRequest(
-      this,
-      base::Bind(&PepperDeviceEnumerationHostHelper::OnNotifyDeviceChange,
-                 base::Unretained(this),
-                 callback_id)));
+  monitor_.reset(new ScopedMonitoringRequest(
+      this, base::Bind(&PepperDeviceEnumerationHostHelper::OnNotifyDeviceChange,
+                       base::Unretained(this), callback_id)));
 
   return monitor_->requested() ? PP_OK : PP_ERROR_FAILED;
 }
 
 int32_t PepperDeviceEnumerationHostHelper::OnStopMonitoringDeviceChange(
     HostMessageContext* /* context */) {
   monitor_.reset(NULL);
   return PP_OK;
 }
 
 void PepperDeviceEnumerationHostHelper::OnEnumerateDevicesComplete(
-    int /* request_id */,
     const std::vector<ppapi::DeviceRefData>& devices) {
   DCHECK(enumerate_devices_context_.is_valid());
 
   enumerate_.reset(NULL);
 
   enumerate_devices_context_.params.set_result(PP_OK);
   resource_host_->host()->SendReply(
       enumerate_devices_context_,
       PpapiPluginMsg_DeviceEnumeration_EnumerateDevicesReply(devices));
   enumerate_devices_context_ = ppapi::host::ReplyMessageContext();
 }
 
 void PepperDeviceEnumerationHostHelper::OnNotifyDeviceChange(
     uint32_t callback_id,
-    int /* request_id */,
     const std::vector<ppapi::DeviceRefData>& devices) {
   resource_host_->host()->SendUnsolicitedReply(
       resource_host_->pp_resource(),
       PpapiPluginMsg_DeviceEnumeration_NotifyDeviceChange(callback_id,
                                                           devices));
 }
 
 }  // namespace content