Fixes for re-enabling more MSVC level 4 warnings: media/ edition

media/video/capture/win/video_capture_device_factory_win.cc

Index: media/video/capture/win/video_capture_device_factory_win.cc
diff --git a/media/video/capture/win/video_capture_device_factory_win.cc b/media/video/capture/win/video_capture_device_factory_win.cc
index a158dc8c33b0749f3910af8c16eb6d151ff04070..a20ecfe8a5a8b5f70c53ceb8663336d91df69a11 100644
--- a/media/video/capture/win/video_capture_device_factory_win.cc
+++ b/media/video/capture/win/video_capture_device_factory_win.cc
@@ -167,23 +167,26 @@ static void GetDeviceNamesMediaFoundation(
   if (!EnumerateVideoDevicesMediaFoundation(&devices, &count))
     return;
 
-  HRESULT hr;
   for (UINT32 i = 0; i < count; ++i) {
-    UINT32 name_size, id_size;
-    ScopedCoMem<wchar_t> name, id;
-    if (SUCCEEDED(hr = devices[i]->GetAllocatedString(
-            MF_DEVSOURCE_ATTRIBUTE_FRIENDLY_NAME, &name, &name_size)) &&
-        SUCCEEDED(hr = devices[i]->GetAllocatedString(
-            MF_DEVSOURCE_ATTRIBUTE_SOURCE_TYPE_VIDCAP_SYMBOLIC_LINK, &id,
-            &id_size))) {
-      std::wstring name_w(name, name_size), id_w(id, id_size);
-      VideoCaptureDevice::Name device(base::SysWideToUTF8(name_w),
-          base::SysWideToUTF8(id_w),
-          VideoCaptureDevice::Name::MEDIA_FOUNDATION);
-      device_names->push_back(device);
-    } else {
-      DLOG(WARNING) << "GetAllocatedString failed: " << std::hex << hr;
+    ScopedCoMem<wchar_t> name;
+    UINT32 name_size;

[ddorwin, 2014/07/08 18:17:50]

nit: initialize? ditto for id_size.

[Peter Kasting, 2014/07/08 18:39:14]

I'm happy to do so if you like; there's no need to, since these are set
unconditionally in the function calls that immediately follow their declarations
(and the compiler is smart enough to figure that out).  Let me know and I'll
stick "= 0"s in.

+    HRESULT hr = devices[i]->GetAllocatedString(
+        MF_DEVSOURCE_ATTRIBUTE_FRIENDLY_NAME, &name, &name_size);
+    if (SUCCEEDED(hr)) {
+      ScopedCoMem<wchar_t> id;
+      UINT32 id_size;
+      hr = devices[i]->GetAllocatedString(
+          MF_DEVSOURCE_ATTRIBUTE_SOURCE_TYPE_VIDCAP_SYMBOLIC_LINK, &id,
+          &id_size);
+      if (SUCCEEDED(hr)) {
+        device_names->push_back(VideoCaptureDevice::Name(
+            base::SysWideToUTF8(std::wstring(name, name_size)),
+            base::SysWideToUTF8(std::wstring(id, id_size)),
+            VideoCaptureDevice::Name::MEDIA_FOUNDATION));
+      }
     }
+    if (FAILED(hr))
+      DLOG(WARNING) << "GetAllocatedString failed: " << std::hex << hr;
     devices[i]->Release();
   }
 }
@@ -286,18 +289,21 @@ static void GetDeviceSupportedFormatsMediaFoundation(
     return;
   }
 
-  HRESULT hr;
   base::win::ScopedComPtr<IMFSourceReader> reader;
-  if (FAILED(hr = MFCreateSourceReaderFromMediaSource(source, NULL,
-                                                      reader.Receive()))) {
+  HRESULT hr =
+      MFCreateSourceReaderFromMediaSource(source, NULL, reader.Receive());
+  if (FAILED(hr)) {
     DLOG(ERROR) << "MFCreateSourceReaderFromMediaSource: " << std::hex << hr;
     return;
   }
 
   DWORD stream_index = 0;
   ScopedComPtr<IMFMediaType> type;
-  while (SUCCEEDED(hr = reader->GetNativeMediaType(
-         MF_SOURCE_READER_FIRST_VIDEO_STREAM, stream_index, type.Receive()))) {
+  for (hr = reader->GetNativeMediaType(kFirstVideoStream, stream_index,
+                                       type.Receive());
+       SUCCEEDED(hr);
+       hr = reader->GetNativeMediaType(kFirstVideoStream, stream_index,
+                                       type.Receive())) {
     UINT32 width, height;
     hr = MFGetAttributeSize(type, MF_MT_FRAME_SIZE, &width, &height);
     if (FAILED(hr)) {
@@ -380,14 +386,13 @@ scoped_ptr<VideoCaptureDevice> VideoCaptureDeviceFactoryWin::Create(
     }
     if (!static_cast<VideoCaptureDeviceMFWin*>(device.get())->Init(source))
       device.reset();
-  } else if (device_name.capture_api_type() ==
-             VideoCaptureDevice::Name::DIRECT_SHOW) {
+  } else {
+    DCHECK_EQ(VideoCaptureDevice::Name::DIRECT_SHOW,

[ddorwin, 2014/07/08 18:17:50]

nit: media/ code prefers "var, const" for code except googletest macros.

[Peter Kasting, 2014/07/08 18:39:14]

Done.

+              device_name.capture_api_type());
     device.reset(new VideoCaptureDeviceWin(device_name));
     DVLOG(1) << " DirectShow Device: " << device_name.name();
     if (!static_cast<VideoCaptureDeviceWin*>(device.get())->Init())
       device.reset();
-  } else {
-    NOTREACHED() << " Couldn't recognize VideoCaptureDevice type";
   }
   return device.Pass();
 }