Orderfile: do not instrument MemoryDumpProvider.

When compiled with devtools_instrumentation_dumping=true, orderfile
profile dumps are triggered by MemoryDumpProvider::OnMemoryDump. We mark
the overriden function used to control the orderfile as
not-to-be-instrumented in order to keep the profile as clean as
possible.

Bug: 843561
Change-Id: I710029753d776fac182b16fcce8aa6c7f5738f83
Reviewed-on: https://chromium-review.googlesource.com/1109970Reviewed-by: Benoit L <lizeb@chromium.org>
Reviewed-by: Egor Pasko <pasko@chromium.org>
Reviewed-by: agrieve <agrieve@chromium.org>
Commit-Queue: agrieve <agrieve@chromium.org>
Cr-Commit-Position: refs/heads/master@{#570031}

base/android/orderfile/orderfile_instrumentation.cc

@@ -75,8 +75,9 @@ std::atomic<int> g_data_index;
 // Dump offsets when a memory dump is requested. Used only if
 // switches::kDevtoolsInstrumentationDumping is set.
 class OrderfileMemoryDumpHook : public base::trace_event::MemoryDumpProvider {
-  bool OnMemoryDump(const base::trace_event::MemoryDumpArgs& args,
-                    base::trace_event::ProcessMemoryDump* pmd) override {
+  NO_INSTRUMENT_FUNCTION bool OnMemoryDump(
+      const base::trace_event::MemoryDumpArgs& args,
+      base::trace_event::ProcessMemoryDump* pmd) override {
     // Disable instrumentation now to cut down on orderfile pollution.
     if (!Disable()) {
       return true;  // A dump has already been started.