Remove ProcessingComponent's dependence on AudioProcessingImpl.

- Move needed accessors to AudioProcessing.
- Inject the crit directly as a dependency.
- Remove the now unneeded EchoCancellationImplWrapper.

BUG=2894
R=aluebs@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/9199004

git-svn-id: http://webrtc.googlecode.com/svn/trunk@5620 4adac7df-926f-26a2-2b94-8c16560cd09d
diff --git a/webrtc/modules/audio_processing/gain_control_impl.h b/webrtc/modules/audio_processing/gain_control_impl.h
index 2de02f6..e1669cc 100644
--- a/webrtc/modules/audio_processing/gain_control_impl.h
+++ b/webrtc/modules/audio_processing/gain_control_impl.h
@@ -17,13 +17,15 @@
 #include "webrtc/modules/audio_processing/processing_component.h"
 
 namespace webrtc {
-class AudioProcessingImpl;
+
 class AudioBuffer;
+class CriticalSectionWrapper;
 
 class GainControlImpl : public GainControl,
                         public ProcessingComponent {
  public:
-  explicit GainControlImpl(const AudioProcessingImpl* apm);
+  GainControlImpl(const AudioProcessing* apm,
+                  CriticalSectionWrapper* crit);
   virtual ~GainControlImpl();
 
   int ProcessRenderAudio(AudioBuffer* audio);
@@ -62,7 +64,8 @@
   virtual int num_handles_required() const OVERRIDE;
   virtual int GetHandleError(void* handle) const OVERRIDE;
 
-  const AudioProcessingImpl* apm_;
+  const AudioProcessing* apm_;
+  CriticalSectionWrapper* crit_;
   Mode mode_;
   int minimum_capture_level_;
   int maximum_capture_level_;