Move talk/app/webrtc to webrtc/api

The previously disabled warnings that were inherited from
talk/build/common.gypi are now replaced by target-specific disabling
of only the failing warnings. Additional disabling was needed since the stricter
compilation warnings that applies to code in webrtc/.

License headers will be updated in a follow-up CL.

Other modifications:
* Updated the header guards.
* Sorted the includes using chromium/src/tools/sort-headers.py
  except for these files:
  talk/app/webrtc/peerconnectionendtoend_unittest.cc
  talk/app/webrtc/java/jni/androidmediadecoder_jni.cc
  talk/app/webrtc/java/jni/androidmediaencoder_jni.cc
  webrtc/media/devices/win32devicemanager.cc

The HAVE_SCTP define was added for the peerconnection_unittests target
in api_tests.gyp.

I also checked that none of
SRTP_RELATIVE_PATH
HAVE_SRTP
HAVE_WEBRTC_VIDEO
HAVE_WEBRTC_VOICE
were used by the talk/app/webrtc code.

For Chromium, the following changes will need to be applied to the roll CL that updates the
DEPS for WebRTC and libjingle:
https://codereview.chromium.org/1615433002

BUG=webrtc:5418
NOPRESUBMIT=True
R=deadbeef@webrtc.org, pthatcher@webrtc.org, tommi@webrtc.org

Review URL: https://codereview.webrtc.org/1610243002 .

Cr-Commit-Position: refs/heads/master@{#11545}
diff --git a/webrtc/api/mediaconstraintsinterface.h b/webrtc/api/mediaconstraintsinterface.h
new file mode 100644
index 0000000..d759e00
--- /dev/null
+++ b/webrtc/api/mediaconstraintsinterface.h
@@ -0,0 +1,141 @@
+/*
+ * libjingle
+ * Copyright 2013 Google Inc.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ *  1. Redistributions of source code must retain the above copyright notice,
+ *     this list of conditions and the following disclaimer.
+ *  2. Redistributions in binary form must reproduce the above copyright notice,
+ *     this list of conditions and the following disclaimer in the documentation
+ *     and/or other materials provided with the distribution.
+ *  3. The name of the author may not be used to endorse or promote products
+ *     derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
+ * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
+ * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
+ * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
+ * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
+ * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+// This file contains the interface for MediaConstraints, corresponding to
+// the definition at
+// http://www.w3.org/TR/mediacapture-streams/#mediastreamconstraints and also
+// used in WebRTC: http://dev.w3.org/2011/webrtc/editor/webrtc.html#constraints.
+
+#ifndef WEBRTC_API_MEDIACONSTRAINTSINTERFACE_H_
+#define WEBRTC_API_MEDIACONSTRAINTSINTERFACE_H_
+
+#include <string>
+#include <vector>
+
+namespace webrtc {
+
+// MediaConstraintsInterface
+// Interface used for passing arguments about media constraints
+// to the MediaStream and PeerConnection implementation.
+class MediaConstraintsInterface {
+ public:
+  struct Constraint {
+    Constraint() {}
+    Constraint(const std::string& key, const std::string value)
+        : key(key), value(value) {
+    }
+    std::string key;
+    std::string value;
+  };
+
+  class Constraints : public std::vector<Constraint> {
+   public:
+    bool FindFirst(const std::string& key, std::string* value) const;
+  };
+
+  virtual const Constraints& GetMandatory() const = 0;
+  virtual const Constraints& GetOptional() const = 0;
+
+  // Constraint keys used by a local video source.
+  // Specified by draft-alvestrand-constraints-resolution-00b
+  static const char kMinAspectRatio[];  // minAspectRatio
+  static const char kMaxAspectRatio[];  // maxAspectRatio
+  static const char kMaxWidth[];  // maxWidth
+  static const char kMinWidth[];  // minWidth
+  static const char kMaxHeight[];  // maxHeight
+  static const char kMinHeight[];  // minHeight
+  static const char kMaxFrameRate[];  // maxFrameRate
+  static const char kMinFrameRate[];  // minFrameRate
+
+  // Constraint keys used by a local audio source.
+  static const char kEchoCancellation[];  // echoCancellation
+
+  // These keys are google specific.
+  static const char kGoogEchoCancellation[];  // googEchoCancellation
+
+  static const char kExtendedFilterEchoCancellation[];  // googEchoCancellation2
+  static const char kDAEchoCancellation[];  // googDAEchoCancellation
+  static const char kAutoGainControl[];  // googAutoGainControl
+  static const char kExperimentalAutoGainControl[];  // googAutoGainControl2
+  static const char kNoiseSuppression[];  // googNoiseSuppression
+  static const char kExperimentalNoiseSuppression[];  // googNoiseSuppression2
+  static const char kHighpassFilter[];  // googHighpassFilter
+  static const char kTypingNoiseDetection[];  // googTypingNoiseDetection
+  static const char kAudioMirroring[];  // googAudioMirroring
+  static const char kAecDump[];               // audioDebugRecording
+
+  // Google-specific constraint keys for a local video source
+  static const char kNoiseReduction[];  // googNoiseReduction
+
+  // Constraint keys for CreateOffer / CreateAnswer
+  // Specified by the W3C PeerConnection spec
+  static const char kOfferToReceiveVideo[];  // OfferToReceiveVideo
+  static const char kOfferToReceiveAudio[];  // OfferToReceiveAudio
+  static const char kVoiceActivityDetection[];  // VoiceActivityDetection
+  static const char kIceRestart[];  // IceRestart
+  // These keys are google specific.
+  static const char kUseRtpMux[];  // googUseRtpMUX
+
+  // Constraints values.
+  static const char kValueTrue[];  // true
+  static const char kValueFalse[];  // false
+
+  // PeerConnection constraint keys.
+  // Temporary pseudo-constraints used to enable DTLS-SRTP
+  static const char kEnableDtlsSrtp[];  // Enable DTLS-SRTP
+  // Temporary pseudo-constraints used to enable DataChannels
+  static const char kEnableRtpDataChannels[];  // Enable RTP DataChannels
+  // Google-specific constraint keys.
+  // Temporary pseudo-constraint for enabling DSCP through JS.
+  static const char kEnableDscp[];  // googDscp
+  // Constraint to enable IPv6 through JS.
+  static const char kEnableIPv6[];  // googIPv6
+  // Temporary constraint to enable suspend below min bitrate feature.
+  static const char kEnableVideoSuspendBelowMinBitrate[];
+      // googSuspendBelowMinBitrate
+  // Constraint to enable combined audio+video bandwidth estimation.
+  static const char kCombinedAudioVideoBwe[];  // googCombinedAudioVideoBwe
+  static const char kScreencastMinBitrate[];  // googScreencastMinBitrate
+  static const char kCpuOveruseDetection[];  // googCpuOveruseDetection
+  static const char kPayloadPadding[];  // googPayloadPadding
+
+  // The prefix of internal-only constraints whose JS set values should be
+  // stripped by Chrome before passed down to Libjingle.
+  static const char kInternalConstraintPrefix[];
+
+ protected:
+  // Dtor protected as objects shouldn't be deleted via this interface
+  virtual ~MediaConstraintsInterface() {}
+};
+
+bool FindConstraint(const MediaConstraintsInterface* constraints,
+                    const std::string& key, bool* value,
+                    size_t* mandatory_constraints);
+
+}  // namespace webrtc
+
+#endif  // WEBRTC_API_MEDIACONSTRAINTSINTERFACE_H_