Adds support for audio capture-effect enumeration on Windows - part 2

Contains additional changes and improvements proposed after landing
by robliao@.

Bug: 1133643
Change-Id: Ib05e3878b70fc10fa5255645d4551639e2c96587
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2514423
Commit-Queue: Henrik Andreasson <henrika@chromium.org>
Reviewed-by: Robert Liao <robliao@chromium.org>
Cr-Commit-Position: refs/heads/master@{#823252}

media/audio/win/audio_low_latency_input_win.cc

@@ -218,6 +218,10 @@ std::string GetOpenLogString(WASAPIAudioInputStream::StreamOpenResult result,
 }
 
 bool InitializeUWPSupport() {
+  // Place the actual body of the initialization in a lambda and store the
+  // result as a static since we don't expect this result to change between
+  // runs.
+  static const bool initialization_result = []() {
     // Windows.Media.Effects and Windows.Media.Devices requires Windows 10 build
     // 10.0.10240.0.
     if (base::win::GetVersion() < base::win::Version::WIN10) {
@@ -237,6 +241,9 @@ bool InitializeUWPSupport() {
       return false;
     }
     return true;
+  }();
+
+  return initialization_result;
 }
 
 }  // namespace
@@ -1169,7 +1176,7 @@ HRESULT WASAPIAudioInputStream::GetAudioCaptureEffects(
   }
 
   return hr;
-}  // namespace media
+}
 
 HRESULT WASAPIAudioInputStream::SetCommunicationsCategoryAndRawCaptureMode() {
   DCHECK(audio_client_.Get());