DesktopCaptureDevice is available when webrtc is enabled.

ENABLED_SCREEN_CAPTURE is not flag to enable DesktopCaptureDevice.
It enables DesktopCaptureDeviceAura (if use_aura=1).

Use BUILDFLAG(ENABLE_WEBRTC) instead of ENABLED_SCREEN_CAPTURE to
use DesktopCaptureDevice in VidepCaptureManager.

BUG=internal b/34176576

Review-Url: https://codereview.chromium.org/2625553003
Cr-Commit-Position: refs/heads/master@{#442957}

content/browser/BUILD.gn

@@ -1499,17 +1499,10 @@ source_set("browser") {
       "//third_party/webrtc/media:rtc_media_base",
       "//third_party/webrtc/modules/desktop_capture:primitives",
     ]
-
-    if (is_linux || is_mac || is_win) {
-      sources += [
-        "media/capture/desktop_capture_device.cc",
-        "media/capture/desktop_capture_device.h",
-      ]
-      deps += [ "//third_party/webrtc/modules/desktop_capture" ]
-    }
   }
 
-  # Desktop screen capture implementations that are not dependent on WebRTC.
+  # Desktop screen capture implementations, conditionally built depending on
+  # the available implementations for each platform.
   if (is_linux || is_mac || is_win) {
     defines += [ "ENABLE_SCREEN_CAPTURE=1" ]
     sources += [
@@ -1540,6 +1533,13 @@ source_set("browser") {
         "media/capture/window_activity_tracker_mac.mm",
       ]
     }
+    if (enable_webrtc) {
+      sources += [
+        "media/capture/desktop_capture_device.cc",
+        "media/capture/desktop_capture_device.h",
+      ]
+      deps += [ "//third_party/webrtc/modules/desktop_capture" ]
+    }
   }
 
   if (is_win) {

content/browser/renderer_host/media/video_capture_manager.cc

@@ -40,17 +40,22 @@
 #include "media/capture/video/video_capture_device_client.h"
 #include "media/capture/video/video_capture_device_factory.h"
 
-#if defined(ENABLE_SCREEN_CAPTURE) && !defined(OS_ANDROID)
+#if defined(ENABLE_SCREEN_CAPTURE)
+
+#if BUILDFLAG(ENABLE_WEBRTC) && !defined(OS_ANDROID)
 #include "content/browser/media/capture/desktop_capture_device.h"
+#endif
+
 #if defined(USE_AURA)
 #include "content/browser/media/capture/desktop_capture_device_aura.h"
 #endif
-#endif
 
-#if defined(ENABLE_SCREEN_CAPTURE) && defined(OS_ANDROID)
+#if defined(OS_ANDROID)
 #include "content/browser/media/capture/screen_capture_device_android.h"
 #endif
 
+#endif  // defined(ENABLE_SCREEN_CAPTURE)
+
 namespace {
 
 class VideoFrameConsumerFeedbackObserverOnTaskRunner
@@ -707,8 +712,10 @@ VideoCaptureManager::DoStartDesktopCaptureOnDeviceThread(
 #if defined(USE_AURA)
     video_capture_device = DesktopCaptureDeviceAura::Create(desktop_id);
 #endif  // defined(USE_AURA)
-    if (!video_capture_device)
-      video_capture_device = DesktopCaptureDevice::Create(desktop_id);
+#if BUILDFLAG(ENABLE_WEBRTC)
+  if (!video_capture_device)
+    video_capture_device = DesktopCaptureDevice::Create(desktop_id);
+#endif  // BUILDFLAG(ENABLE_WEBRTC)
 #endif  // defined (OS_ANDROID)
   }
 #endif  // defined(ENABLE_SCREEN_CAPTURE)
@@ -1227,7 +1234,7 @@ void VideoCaptureManager::SetDesktopCaptureWindowIdOnDeviceThread(
     media::VideoCaptureDevice* device,
     gfx::NativeViewId window_id) {
   DCHECK(IsOnDeviceThread());
-#if defined(ENABLE_SCREEN_CAPTURE) && !defined(OS_ANDROID)
+#if defined(ENABLE_SCREEN_CAPTURE) && BUILDFLAG(ENABLE_WEBRTC) && !defined(OS_ANDROID)
   DesktopCaptureDevice* desktop_device =
       static_cast<DesktopCaptureDevice*>(device);
   desktop_device->SetNotificationWindowId(window_id);