Media Remoting Clean-up: Less-redundant naming, style consistency, etc.

media/remoting/remoting_cdm_context.h

Index: media/remoting/remoting_cdm_context.h
diff --git a/media/remoting/remoting_cdm_context.h b/media/remoting/remoting_cdm_context.h
index f7c3284d1baccaac47d7c380915b41db34e3f4bf..bcf16c4b7a41f34d629080dc3111bdfb794b3afc 100644
--- a/media/remoting/remoting_cdm_context.h
+++ b/media/remoting/remoting_cdm_context.h
@@ -8,11 +8,13 @@
 #include "media/base/cdm_context.h"
 
 namespace media {
+namespace remoting {
 
 class RemotingCdm;
-class RemotingSourceImpl;
 
 // TODO(xjz): Merge this with erickung's implementation.
+// TODO(miu): This class should just be merged into RemotingCdm and implement
+// both the CDM and CdmContext interfaces.

[xjz, 2017/01/21 06:12:34]

This is required by media owner. The following is xhwang@'s comment on my
original CL: "The purpose that we have CdmContext is to isolate the media player
(e.g. renderer) from accessing
the CDM directly. Therefore, it's more desirable that we cast CdmContext to a
RemotingCdmContext here, and get GetRemotingSource() there, instead of getting
the CDM from the context, which defies the purpose of CdmContext."

[miu, 2017/01/23 20:57:36]

Interesting point. I looked into this more, and I think we can still merge the
classes *if* we get rid of the cdm() (or GetRemotingSource()) accessor. Instead
of the accessor, we could provide a new static function in SharedSession:

  // If CdmContext represents a remoting implementation, return a pointer to the
SharedSession it
  // is using. Otherwise, return nullptr.
  SharedSession* GetForCdmContext(CdmContext* context);

Then, in the controller (or renderer), there is no direct pointer to the Cdm.
All they would have is a CdmContext* (and no way to downcast it to the merged
impl class).

I think that would satisfy all requirements, and allow us to get rid of this
extra class that is only owned by RemotingCdm and points back to it.

WDYT? (For a later CL; not this one.)

[xjz, 2017/01/23 23:08:13]

sgtm.

 class RemotingCdmContext : public CdmContext {
  public:
   explicit RemotingCdmContext(RemotingCdm* remoting_cdm);
@@ -22,7 +24,7 @@ class RemotingCdmContext : public CdmContext {
   // pointer to it. Otherwise, return nullptr.
   static RemotingCdmContext* From(CdmContext* cdm_context);
 
-  RemotingSourceImpl* GetRemotingSource();
+  RemotingCdm* cdm() const { return remoting_cdm_; }

[xjz, 2017/01/21 06:12:34]

This accessor can access the CDM directly. I am OK with this, but it seems
doesn't follow the purpose of CdmContext as commented above. Since the only
thing we want from CDM is the RemotingSource, it sounds good to just have a
GetSession() function. WDYT?

[miu, 2017/01/23 20:57:37]

For now, I put this back to a SharedSession getter. (See comment above for other
details.)

 
   // CdmContext implementations.
   Decryptor* GetDecryptor() override;
@@ -35,6 +37,7 @@ class RemotingCdmContext : public CdmContext {
   DISALLOW_COPY_AND_ASSIGN(RemotingCdmContext);
 };
 
+}  // namespace remoting
 }  // namespace media
 
 #endif  // MEDIA_REMOTING_REMOTING_CDM_CONTEXT_H_