Move ensure keyboard mic check in MediaStreamManager to SetupRequest.

Since we on ChromeOS don't (always) need to enumerate devices at all.

BUG=345296
NOTRY=true

Review URL: https://codereview.chromium.org/596233003

Cr-Commit-Position: refs/heads/master@{#296420}

content/browser/renderer_host/media/media_stream_manager.cc

@@ -1082,16 +1082,6 @@ void MediaStreamManager::StartEnumeration(DeviceRequest* request) {
   // Start monitoring the devices when doing the first enumeration.
   StartMonitoring();
 
-#if defined(OS_CHROMEOS)
-  if (!has_checked_keyboard_mic_) {
-    has_checked_keyboard_mic_ = true;
-    BrowserThread::PostTask(
-        BrowserThread::UI, FROM_HERE,
-        base::Bind(&MediaStreamManager::CheckKeyboardMicOnUIThread,
-                   base::Unretained(this)));
-  }
-#endif
-
   // Start enumeration for devices of all requested device types.
   const MediaStreamType streams[] = { request->audio_type(),
                                       request->video_type() };
@@ -1234,6 +1224,10 @@ void MediaStreamManager::SetupRequest(const std::string& label) {
     return;
   }
 
+#if defined(OS_CHROMEOS)
+  EnsureKeyboardMicChecked();
+#endif
+
   if (!is_web_contents_capture && !is_screen_capture) {
     if (EnumerationRequired(&audio_enumeration_cache_, audio_type) ||
         EnumerationRequired(&video_enumeration_cache_, video_type)) {
@@ -2098,6 +2092,17 @@ void MediaStreamManager::OnMediaStreamUIWindowId(MediaStreamType video_type,
 }
 
 #if defined(OS_CHROMEOS)
+void MediaStreamManager::EnsureKeyboardMicChecked() {
+  DCHECK_CURRENTLY_ON(BrowserThread::IO);
+  if (!has_checked_keyboard_mic_) {
+    has_checked_keyboard_mic_ = true;
+    BrowserThread::PostTask(
+        BrowserThread::UI, FROM_HERE,
+        base::Bind(&MediaStreamManager::CheckKeyboardMicOnUIThread,
+                   base::Unretained(this)));
+  }
+}
+
 void MediaStreamManager::CheckKeyboardMicOnUIThread() {
   DCHECK_CURRENTLY_ON(BrowserThread::UI);
 

content/browser/renderer_host/media/media_stream_manager.h

@@ -364,6 +364,11 @@ class CONTENT_EXPORT MediaStreamManager
                                gfx::NativeViewId window_id);
 
 #if defined(OS_CHROMEOS)
+  // Ensures that we have checked for presence of a keyboard mic. This is only
+  // done once. This function should be called before posting a request on the
+  // UI thread.
+  void EnsureKeyboardMicChecked();
+
   // Checks if the system has a keyboard mic, and if so, inform the audio
   // manager via SetKeyboardMicOnDeviceThread().
   void CheckKeyboardMicOnUIThread();