Fixed a potential deadlock problem in the AGC.

webrtc/modules/audio_processing/gain_control_impl.cc

Index: webrtc/modules/audio_processing/gain_control_impl.cc
diff --git a/webrtc/modules/audio_processing/gain_control_impl.cc b/webrtc/modules/audio_processing/gain_control_impl.cc
index db1c585ca95962f5140e7430daedc1683ca21f8e..b82978d19c8a12301735680dd50810b85326817d 100644
--- a/webrtc/modules/audio_processing/gain_control_impl.cc
+++ b/webrtc/modules/audio_processing/gain_control_impl.cc
@@ -336,25 +336,31 @@ GainControl::Mode GainControlImpl::mode() const {
 
 int GainControlImpl::set_analog_level_limits(int minimum,
                                              int maximum) {
-  rtc::CritScope cs(crit_capture_);
-  if (minimum < 0) {
-    return AudioProcessing::kBadParameterError;
-  }
+  size_t num_proc_channels_local = 0u;
+  int sample_rate_hz_local = 0;
+  {
+    rtc::CritScope cs(crit_capture_);
+    if (minimum < 0) {

[the sun, 2016/03/24 12:29:29]

All parameter checking should go first in the function, before taking the
critsect.

[peah-webrtc, 2016/03/24 12:46:40]

Good point!

Done.

+      return AudioProcessing::kBadParameterError;
+    }
 
-  if (maximum > 65535) {
-    return AudioProcessing::kBadParameterError;
-  }
+    if (maximum > 65535) {
+      return AudioProcessing::kBadParameterError;
+    }
 
-  if (maximum < minimum) {
-    return AudioProcessing::kBadParameterError;
-  }
+    if (maximum < minimum) {
+      return AudioProcessing::kBadParameterError;
+    }
 
-  minimum_capture_level_ = minimum;
-  maximum_capture_level_ = maximum;
+    minimum_capture_level_ = minimum;
+    maximum_capture_level_ = maximum;
 
-  RTC_DCHECK(num_proc_channels_);
-  RTC_DCHECK(sample_rate_hz_);
-  Initialize(*num_proc_channels_, *sample_rate_hz_);
+    RTC_DCHECK(num_proc_channels_);
+    RTC_DCHECK(sample_rate_hz_);
+    num_proc_channels_local = *num_proc_channels_;
+    sample_rate_hz_local = *sample_rate_hz_;
+  }
+  Initialize(num_proc_channels_local, sample_rate_hz_local);
   return AudioProcessing::kNoError;
 }