Let Contraints Controll Mute/Unmute Audio Local Playback For Desktop Sharing

content/public/browser/web_contents_media_capture_id.h

Index: content/public/browser/web_contents_media_capture_id.h
diff --git a/content/public/browser/web_contents_media_capture_id.h b/content/public/browser/web_contents_media_capture_id.h
index 84d91dbe7da4595ef63eed60a67af8bf504e93e2..e159eeb23b031a5f863254ef7ab36c864455dd1a 100644
--- a/content/public/browser/web_contents_media_capture_id.h
+++ b/content/public/browser/web_contents_media_capture_id.h
@@ -21,10 +21,12 @@ struct CONTENT_EXPORT WebContentsMediaCaptureId {
 
   WebContentsMediaCaptureId(int render_process_id,
                             int main_render_frame_id,
-                            bool enable_auto_throttling)
+                            bool enable_auto_throttling,
+                            bool mute_source)
       : render_process_id(render_process_id),
         main_render_frame_id(main_render_frame_id),
-        enable_auto_throttling(enable_auto_throttling) {}
+        enable_auto_throttling(enable_auto_throttling),
+        mute_source(mute_source) {}
 
   bool operator<(const WebContentsMediaCaptureId& other) const;
   bool operator==(const WebContentsMediaCaptureId& other) const;
@@ -39,6 +41,7 @@ struct CONTENT_EXPORT WebContentsMediaCaptureId {
   int main_render_frame_id = MSG_ROUTING_NONE;
 
   bool enable_auto_throttling = false;
+  bool mute_source = false;
 
   // Create WebContentsMediaCaptureId based on a string.
   static WebContentsMediaCaptureId Parse(const std::string& str);
@@ -52,9 +55,15 @@ struct CONTENT_EXPORT WebContentsMediaCaptureId {
                                       int* render_process_id,
                                       int* main_render_frame_id);
 
-  // Parses the media stream request |device_id| and returns true if both 1) the
-  // format is valid, and 2) the throttling option is set to auto.
-  static bool IsAutoThrottlingOptionSet(const std::string& device_id);
+  // Parses the media stream request |device_id| and returns true if the
+  // format is valid. |*auto_throttling| will be stored whether the |device_id|
+  // indicated auto throttling. |*mute_source| will stored whether |device_id|
+  // requests us to mute the source audio during sharing.
+  // The caller can pass nullptr for either |auto_throttling| or |mute_source|,
+  // if the value is uninteresting.
+  static bool ExtractOptions(const std::string& device_id,

[miu, 2016/09/07 21:10:03]

Looking at the calls to this function, only one of the two bool* is ever
provided. This suggests you should either: 1) Keep the
IsAutoThrottlingOptionSet() function and add a new IsMuteSourceOptionSet()
function; or 2) Delete the IsAudioThrottlingOptionSet() function and make all
callers just use Parse() and then read the bool field they are interested in
from the WebContentsMediaCaptureId struct.

I'll leave it up to you which you think fits cleanest. ;)

[qiangchen, 2016/09/09 23:32:08]

Done.

+                             bool* auto_throttling,
+                             bool* mute_source);
 };
 
 }  // namespace content