Obj-C SDK Cleanup

This CL separates the files under sdk/objc into logical directories, replacing
the previous file layout under Framework/.

A long term goal is to have some system set up to generate the files under
sdk/objc/api (the PeerConnection API wrappers) from the C++ code. In the shorter
term the goal is to abstract out shared concepts from these classes in order to
make them as uniform as possible.

The separation into base/, components/, and helpers/ are to differentiate between
the base layer's common protocols, various utilities and the actual platform
specific components.

The old directory layout that resembled a framework's internal layout is not
necessary, since it is generated by the framework target when building it.

Bug: webrtc:9627
Change-Id: Ib084fd83f050ae980649ca99e841f4fb0580bd8f
Reviewed-on: https://webrtc-review.googlesource.com/94142
Reviewed-by: Kári Helgason <kthelgason@webrtc.org>
Reviewed-by: Mirko Bonadei <mbonadei@webrtc.org>
Reviewed-by: Rasmus Brandt <brandtr@webrtc.org>
Reviewed-by: Henrik Andreassson <henrika@webrtc.org>
Commit-Queue: Anders Carlsson <andersc@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#24493}
diff --git a/sdk/objc/base/RTCLogging.h b/sdk/objc/base/RTCLogging.h
new file mode 100644
index 0000000..be62db2
--- /dev/null
+++ b/sdk/objc/base/RTCLogging.h
@@ -0,0 +1,66 @@
+/*
+ *  Copyright 2015 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#import <Foundation/Foundation.h>
+
+#import "RTCMacros.h"
+
+// Subset of rtc::LoggingSeverity.
+typedef NS_ENUM(NSInteger, RTCLoggingSeverity) {
+  RTCLoggingSeverityVerbose,
+  RTCLoggingSeverityInfo,
+  RTCLoggingSeverityWarning,
+  RTCLoggingSeverityError,
+};
+
+// Wrapper for C++ RTC_LOG(sev) macros.
+// Logs the log string to the webrtc logstream for the given severity.
+RTC_EXTERN void RTCLogEx(RTCLoggingSeverity severity, NSString* log_string);
+
+// Wrapper for rtc::LogMessage::LogToDebug.
+// Sets the minimum severity to be logged to console.
+RTC_EXTERN void RTCSetMinDebugLogLevel(RTCLoggingSeverity severity);
+
+// Returns the filename with the path prefix removed.
+RTC_EXTERN NSString* RTCFileName(const char* filePath);
+
+// Some convenience macros.
+
+#define RTCLogString(format, ...)                                           \
+  [NSString stringWithFormat:@"(%@:%d %s): " format, RTCFileName(__FILE__), \
+                             __LINE__, __FUNCTION__, ##__VA_ARGS__]
+
+#define RTCLogFormat(severity, format, ...)                     \
+  do {                                                          \
+    NSString* log_string = RTCLogString(format, ##__VA_ARGS__); \
+    RTCLogEx(severity, log_string);                             \
+  } while (false)
+
+#define RTCLogVerbose(format, ...) \
+  RTCLogFormat(RTCLoggingSeverityVerbose, format, ##__VA_ARGS__)
+
+#define RTCLogInfo(format, ...) \
+  RTCLogFormat(RTCLoggingSeverityInfo, format, ##__VA_ARGS__)
+
+#define RTCLogWarning(format, ...) \
+  RTCLogFormat(RTCLoggingSeverityWarning, format, ##__VA_ARGS__)
+
+#define RTCLogError(format, ...) \
+  RTCLogFormat(RTCLoggingSeverityError, format, ##__VA_ARGS__)
+
+#if !defined(NDEBUG)
+#define RTCLogDebug(format, ...) RTCLogInfo(format, ##__VA_ARGS__)
+#else
+#define RTCLogDebug(format, ...) \
+  do {                           \
+  } while (false)
+#endif
+
+#define RTCLog(format, ...) RTCLogInfo(format, ##__VA_ARGS__)