Add linux ftrace support

Original author: Andrzej Surdej <Andrzej_Surdej@comcast.com>
Original pull request: 1462

Add WebKit tracing with linux 'ftrace' that can be used on STB devices.
Write tracing points into 'trace_marker' file with 'perfetto'
compatible format.
The results can be collected and visualized by 'perfetto'

Note: Minor adjustments to original pull request for wpe-2.46 up-streaming

Author: filipe-norte-red

Source/WTF/wtf/PlatformWPE.cmake

@@ -50,6 +50,7 @@ list(APPEND WTF_PUBLIC_HEADERS
     linux/CurrentProcessMemoryStatus.h
     linux/ProcessMemoryFootprint.h
     linux/RealTimeThreads.h
+    linux/SystemTracingFTrace.h
 
     unix/UnixFileDescriptor.h
 )

Source/WTF/wtf/SystemTracing.h

@@ -193,6 +193,10 @@ enum TracePointCode {
 #include <wtf/glib/SysprofAnnotator.h>
 #endif
 
+#if USE(LINUX_FTRACE)
+#include <wtf/linux/SystemTracingFTrace.h>
+#endif
+
 namespace WTF {
 
 inline void tracePoint(TracePointCode code, uint64_t data1 = 0, uint64_t data2 = 0, uint64_t data3 = 0, uint64_t data4 = 0)
@@ -206,6 +210,11 @@ inline void tracePoint(TracePointCode code, uint64_t data1 = 0, uint64_t data2 =
     UNUSED_PARAM(data2);
     UNUSED_PARAM(data3);
     UNUSED_PARAM(data4);
+#elif USE(LINUX_FTRACE)
+    SystemTracingFTrace::instance().tracePoint(code, data1);
+    UNUSED_PARAM(data2);
+    UNUSED_PARAM(data3);
+    UNUSED_PARAM(data4);
 #else
     UNUSED_PARAM(code);
     UNUSED_PARAM(data1);