Change kEchoCancellation to be 'echoCancellation'.
This is the second cl in WebRTC for this change and will be landed after Chromium has been updated to use kGooglEchoCancellation where that variant is required. See also the first part: https://codereview.webrtc.org/1179233003

BUG=webrtc:4747
R=andrew@webrtc.org

Review URL: https://codereview.webrtc.org/1185963003

Cr-Commit-Position: refs/heads/master@{#9490}
diff --git a/talk/app/webrtc/mediaconstraintsinterface.cc b/talk/app/webrtc/mediaconstraintsinterface.cc
index 2c918d8..66a2ad2 100644
--- a/talk/app/webrtc/mediaconstraintsinterface.cc
+++ b/talk/app/webrtc/mediaconstraintsinterface.cc
@@ -47,7 +47,7 @@
 
 // Audio constraints.
 const char MediaConstraintsInterface::kEchoCancellation[] =
-    "googEchoCancellation";
+    "echoCancellation";
 const char MediaConstraintsInterface::kGoogEchoCancellation[] =
     "googEchoCancellation";
 const char MediaConstraintsInterface::kExtendedFilterEchoCancellation[] =
diff --git a/talk/app/webrtc/mediaconstraintsinterface.h b/talk/app/webrtc/mediaconstraintsinterface.h
index e58b2f8..777c3cc 100644
--- a/talk/app/webrtc/mediaconstraintsinterface.h
+++ b/talk/app/webrtc/mediaconstraintsinterface.h
@@ -72,12 +72,9 @@
   static const char kMinFrameRate[];  // minFrameRate
 
   // Constraint keys used by a local audio source.
+  static const char kEchoCancellation[];  // echoCancellation
+
   // These keys are google specific.
-  // TODO(tommi): Change kEchoCancellation to be "echoCancellation" once
-  // Chrome has been updated to use kGoogEchoCancellation where the 'goog'
-  // variant is needed.
-  // See https://code.google.com/p/webrtc/issues/detail?id=4747
-  static const char kEchoCancellation[];  // googEchoCancellation
   static const char kGoogEchoCancellation[];  // googEchoCancellation
 
   static const char kExtendedFilterEchoCancellation[];  // googEchoCancellation2