Add allocator interface for use by cdm_adapter

media/cdm/cdm_helpers.h

Index: media/cdm/cdm_helpers.h
diff --git a/media/cdm/cdm_helpers.h b/media/cdm/cdm_helpers.h
index ea813767938bf12a109d35a1e43085d60f8e7021..8604eb1eed5533e6fa02be5bb0b87e0f92c9d5e1 100644
--- a/media/cdm/cdm_helpers.h
+++ b/media/cdm/cdm_helpers.h
@@ -10,8 +10,15 @@
 #include "base/macros.h"
 #include "media/cdm/api/content_decryption_module.h"
 
+#if !defined(USE_PPAPI_CDM_ADAPTER)
+#include "base/memory/ref_counted.h"
+#include "ui/gfx/geometry/size.h"
+#endif
+
 namespace media {
 
+class VideoFrame;
+
 class DecryptedBlockImpl : public cdm::DecryptedBlock {
  public:
   DecryptedBlockImpl();
@@ -33,7 +40,7 @@ class DecryptedBlockImpl : public cdm::DecryptedBlock {
 class VideoFrameImpl : public cdm::VideoFrame {
  public:
   VideoFrameImpl();
-  ~VideoFrameImpl() final;
+  ~VideoFrameImpl() override;
 
   // cdm::VideoFrame implementation.
   void SetFormat(cdm::VideoFormat format) final;
@@ -49,7 +56,17 @@ class VideoFrameImpl : public cdm::VideoFrame {
   void SetTimestamp(int64_t timestamp) final;
   int64_t Timestamp() const final;
 
- private:
+#if !defined(USE_PPAPI_CDM_ADAPTER)
+  // Create a media::VideoFrame based on the data contained in this object.
+  // The returned object will own the memory in FrameBuffer and will be

[xhwang, 2016/02/12 08:45:30]

nit: s/the memory in FrameBuffer/|frame_buffer_| ?

[jrummell, 2016/02/12 23:14:20]

Done.

+  // responsible for calling Destroy() on it when the media::VideoFrame no
+  // longer needs it. After CreateVideoFrame() is called the VideoFrameImpl
+  // will no longer have a reference to the memory.

[xhwang, 2016/02/12 08:45:30]

nit: s/the VideoFrameImpl will no longer have a reference to the
memory/|frame_buffer_| will be cleared/.

[jrummell, 2016/02/12 23:14:20]

Removed the whole sentence since it simply restates what the second sentence
says.

+  virtual scoped_refptr<media::VideoFrame> CreateVideoFrame(
+      gfx::Size natural_size) = 0;

[xhwang, 2016/02/12 08:45:30]

nit: Actually, this is not a typical "Create" call. It's more like "move" or
"convert" this into a media::VideoFrame. 
How about something like TransformToVideoFrame()?

Also in the comment we need to make the precondition and postcondition clear,
something like the precondition is that |this| needs to be initialized. The post
condition is that |this| will no longer own the buffer, etc.

[jrummell, 2016/02/12 23:14:20]

Done.

+#endif
+
+ protected:
   // The video buffer format.
   cdm::VideoFormat format_;
 
@@ -70,6 +87,7 @@ class VideoFrameImpl : public cdm::VideoFrame {
   // Presentation timestamp in microseconds.
   int64_t timestamp_;
 
+ private:
   DISALLOW_COPY_AND_ASSIGN(VideoFrameImpl);
 };