Fix compilation if HAVE_WEBRTC_VIDEO is not defined.

This CL fixes compiler / linker errors that occur if HAVE_WEBRTC_VIDEO is
not defined and introduces a new class NullWebRtcVideoEngine to use in
that case.

BUG=
TEST=remove define HAVE_WEBRTC_VIDEO from talk/build/common.gypi, run gclient runhooks and compile

Review URL: https://codereview.webrtc.org/1621453005

Cr-Commit-Position: refs/heads/master@{#11387}

talk/libjingle.gyp

@@ -540,6 +540,7 @@
         'media/devices/yuvframescapturer.h',
         'media/sctp/sctpdataengine.cc',
         'media/sctp/sctpdataengine.h',
+        'media/webrtc/nullwebrtcvideoengine.h',
         'media/webrtc/simulcast.cc',
         'media/webrtc/simulcast.h',
         'media/webrtc/webrtccommon.h',

talk/libjingle_tests.gyp

@@ -96,6 +96,7 @@
         'media/devices/dummydevicemanager_unittest.cc',
         'media/devices/filevideocapturer_unittest.cc',
         'media/sctp/sctpdataengine_unittest.cc',
+        'media/webrtc/nullwebrtcvideoengine_unittest.cc',
         'media/webrtc/simulcast_unittest.cc',
         'media/webrtc/webrtcmediaengine_unittest.cc',
         'media/webrtc/webrtcvideocapturer_unittest.cc',

talk/media/webrtc/nullwebrtcvideoengine.h

@@ -0,0 +1,81 @@
+/*
+ * libjingle
+ * Copyright 2016 Google Inc.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ *  1. Redistributions of source code must retain the above copyright notice,
+ *     this list of conditions and the following disclaimer.
+ *  2. Redistributions in binary form must reproduce the above copyright notice,
+ *     this list of conditions and the following disclaimer in the documentation
+ *     and/or other materials provided with the distribution.
+ *  3. The name of the author may not be used to endorse or promote products
+ *     derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
+ * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
+ * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
+ * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
+ * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
+ * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef TALK_MEDIA_WEBRTC_NULLWEBRTCVIDEOENGINE_H_
+#define TALK_MEDIA_WEBRTC_NULLWEBRTCVIDEOENGINE_H_
+
+#include <vector>
+
+#include "talk/media/base/mediachannel.h"
+#include "talk/media/base/mediaengine.h"
+
+namespace webrtc {
+
+class Call;
+
+}  // namespace webrtc
+
+
+namespace cricket {
+
+class VideoMediaChannel;
+class WebRtcVideoDecoderFactory;
+class WebRtcVideoEncoderFactory;
+
+// Video engine implementation that does nothing and can be used in
+// CompositeMediaEngine.
+class NullWebRtcVideoEngine {
+ public:
+  NullWebRtcVideoEngine() {}
+  ~NullWebRtcVideoEngine() {}
+
+  void SetExternalDecoderFactory(WebRtcVideoDecoderFactory* decoder_factory) {}
+  void SetExternalEncoderFactory(WebRtcVideoEncoderFactory* encoder_factory) {}
+
+  void Init() {}
+
+  const std::vector<VideoCodec>& codecs() {
+    return codecs_;
+  }
+
+  RtpCapabilities GetCapabilities() {
+    RtpCapabilities capabilities;
+    return capabilities;
+  }
+
+  VideoMediaChannel* CreateChannel(webrtc::Call* call,
+      const VideoOptions& options) {
+    return nullptr;
+  }
+
+ private:
+  std::vector<VideoCodec> codecs_;
+};
+
+}  // namespace cricket
+
+#endif  // TALK_MEDIA_WEBRTC_NULLWEBRTCVIDEOENGINE_H_

talk/media/webrtc/nullwebrtcvideoengine_unittest.cc

@@ -0,0 +1,56 @@
+/*
+ * libjingle
+ * Copyright 2016 Google Inc.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ *  1. Redistributions of source code must retain the above copyright notice,
+ *     this list of conditions and the following disclaimer.
+ *  2. Redistributions in binary form must reproduce the above copyright notice,
+ *     this list of conditions and the following disclaimer in the documentation
+ *     and/or other materials provided with the distribution.
+ *  3. The name of the author may not be used to endorse or promote products
+ *     derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
+ * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
+ * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
+ * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
+ * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
+ * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "testing/gtest/include/gtest/gtest.h"
+
+#include "talk/media/webrtc/nullwebrtcvideoengine.h"
+#include "talk/media/webrtc/webrtcvoiceengine.h"
+
+namespace cricket {
+
+class WebRtcMediaEngineNullVideo
+    : public CompositeMediaEngine<WebRtcVoiceEngine, NullWebRtcVideoEngine> {
+ public:
+  WebRtcMediaEngineNullVideo(webrtc::AudioDeviceModule* adm,
+                             WebRtcVideoEncoderFactory* encoder_factory,
+                             WebRtcVideoDecoderFactory* decoder_factory) {
+    voice_.SetAudioDeviceModule(adm);
+    video_.SetExternalDecoderFactory(decoder_factory);
+    video_.SetExternalEncoderFactory(encoder_factory);
+  }
+};
+
+// Simple test to check if NullWebRtcVideoEngine implements the methods
+// required by CompositeMediaEngine.
+TEST(NullWebRtcVideoEngineTest, CheckInterface) {
+  WebRtcMediaEngineNullVideo engine(nullptr, nullptr, nullptr);
+
+  EXPECT_TRUE(engine.Init(rtc::Thread::Current()));
+  engine.Terminate();
+}
+
+}  // namespace cricket

talk/media/webrtc/webrtcmediaengine.cc

@@ -29,13 +29,21 @@
 
 #include <algorithm>
 
+#ifdef HAVE_WEBRTC_VIDEO
 #include "talk/media/webrtc/webrtcvideoengine2.h"
+#else
+#include "talk/media/webrtc/nullwebrtcvideoengine.h"
+#endif
 #include "talk/media/webrtc/webrtcvoiceengine.h"
 
 namespace cricket {
 
 class WebRtcMediaEngine2
+#ifdef HAVE_WEBRTC_VIDEO
     : public CompositeMediaEngine<WebRtcVoiceEngine, WebRtcVideoEngine2> {
+#else
+    : public CompositeMediaEngine<WebRtcVoiceEngine, NullWebRtcVideoEngine> {
+#endif
  public:
   WebRtcMediaEngine2(webrtc::AudioDeviceModule* adm,
                      WebRtcVideoEncoderFactory* encoder_factory,

talk/media/webrtc/webrtcvideocapturer_unittest.cc

@@ -25,6 +25,8 @@
  * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
+#ifdef HAVE_WEBRTC_VIDEO
+
 #include <stdio.h>
 #include <vector>
 #include "talk/media/base/testutils.h"
@@ -146,3 +148,5 @@ TEST_F(WebRtcVideoCapturerTest, TestCaptureWithoutInit) {
   EXPECT_TRUE(capturer_->GetCaptureFormat() == NULL);
   EXPECT_FALSE(capturer_->IsRunning());
 }
+
+#endif  // HAVE_WEBRTC_VIDEO

talk/media/webrtc/webrtcvideocapturerfactory.cc

@@ -32,12 +32,16 @@
 namespace cricket {
 
 VideoCapturer* WebRtcVideoDeviceCapturerFactory::Create(const Device& device) {
+#ifdef HAVE_WEBRTC_VIDEO
   rtc::scoped_ptr<WebRtcVideoCapturer> capturer(
       new WebRtcVideoCapturer());
   if (!capturer->Init(device)) {
-    return NULL;
+    return nullptr;
   }
   return capturer.release();
+#else
+  return nullptr;
+#endif
 }
 
 }  // namespace cricket

talk/media/webrtc/webrtcvideoengine2_unittest.cc

@@ -25,6 +25,8 @@
  * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
+#ifdef HAVE_WEBRTC_VIDEO
+
 #include <algorithm>
 #include <map>
 #include <vector>
@@ -3404,3 +3406,5 @@ TEST_F(WebRtcVideoChannel2SimulcastTest,
 }
 
 }  // namespace cricket
+
+#endif  // HAVE_WEBRTC_VIDEO