fix debug markers when implemented with systrace

when debug markers are implemented with systrace, begin/end can is not
guaranteed to happen in the same C++ scope, so we can't really use 
other scoped systraces.

filament/backend/src/CommandStream.cpp

@@ -20,11 +20,16 @@
 #include <utils/CallStack.h>
 #endif
 
+#include <utils/compiler.h>
 #include <utils/Log.h>
+#include <utils/ostream.h>
 #include <utils/Profiler.h>
 #include <utils/Systrace.h>
 
+#include <cstddef>
 #include <functional>
+#include <string>
+#include <utility>
 
 #ifdef __ANDROID__
 #include <sys/system_properties.h>
@@ -74,8 +79,8 @@ CommandStream::CommandStream(Driver& driver, CircularBuffer& buffer) noexcept
 }
 
 void CommandStream::execute(void* buffer) {
-    SYSTRACE_CALL();
-    SYSTRACE_CONTEXT();
+    // NOTE: we can't use SYSTRACE_CALL() or similar here because, execute() below, also
+    // uses systrace BEGIN/END and the END is not guaranteed to be happening in this scope.
 
     Profiler profiler;
 
@@ -100,6 +105,7 @@ void CommandStream::execute(void* buffer) {
             // we want to remove all this when tracing is completely disabled
             profiler.stop();
             UTILS_UNUSED Profiler::Counters const counters = profiler.readCounters();
+            SYSTRACE_CONTEXT();
             SYSTRACE_VALUE32("GLThread (I)", counters.getInstructions());
             SYSTRACE_VALUE32("GLThread (C)", counters.getCpuCycles());
             SYSTRACE_VALUE32("GLThread (CPI x10)", counters.getCPI() * 10);

filament/src/fg/FrameGraph.cpp

@@ -195,12 +195,11 @@ FrameGraph& FrameGraph::compile() noexcept {
 
 void FrameGraph::execute(backend::DriverApi& driver) noexcept {
 
-    SYSTRACE_CALL();
-
     bool const useProtectedMemory = mMode == Mode::PROTECTED;
     auto const& passNodes = mPassNodes;
     auto& resourceAllocator = mResourceAllocator;
 
+    SYSTRACE_NAME("FrameGraph");
     driver.pushGroupMarker("FrameGraph");
 
     auto first = passNodes.begin();
@@ -211,7 +210,6 @@ void FrameGraph::execute(backend::DriverApi& driver) noexcept {
         assert_invariant(!node->isCulled());
 
         SYSTRACE_NAME(node->getName());
-
         driver.pushGroupMarker(node->getName());
 
         // devirtualize resourcesList
@@ -229,7 +227,6 @@ void FrameGraph::execute(backend::DriverApi& driver) noexcept {
             assert_invariant(resource->last == node);
             resource->destroy(resourceAllocator);
         }
-
         driver.popGroupMarker();
     }
     driver.popGroupMarker();