gpu: Add tracing for flush workaround on mac.

R=kbr@chromium.org

Bug: 1070464
Change-Id: Ia7a5b82e9aae126b1a6860224879b7638940102e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2154374
Auto-Submit: Khushal <khushalsagar@chromium.org>
Commit-Queue: Kenneth Russell <kbr@chromium.org>
Reviewed-by: Kenneth Russell <kbr@chromium.org>
Cr-Commit-Position: refs/heads/master@{#760175}

gpu/command_buffer/service/raster_decoder.cc

@@ -399,6 +399,7 @@ class RasterDecoderImpl final : public RasterDecoder,
     // macOS OpenGL driver.
     // https://crbug.com/906453
     if (!flush_workaround_disabled_for_test_) {
+      TRACE_EVENT0("gpu", "RasterDecoderImpl::FlushToWorkAroundMacCrashes");
       if (gr_context())
         gr_context()->flush();
       api()->glFlushFn();

ui/gl/gl_context.cc

@@ -272,6 +272,7 @@ void GLContext::DestroyBackpressureFences() {
 void GLContext::FlushForDriverCrashWorkaround() {
   if (!IsCurrent(nullptr))
     return;
+  TRACE_EVENT0("gpu", "GLContext::FlushForDriverCrashWorkaround");
   glFlush();
 }
 #endif

ui/gl/init/create_gr_gl_interface.cc

@@ -6,6 +6,7 @@
 
 #include "base/metrics/histogram_macros.h"
 #include "base/no_destructor.h"
+#include "base/trace_event/trace_event.h"
 #include "build/build_config.h"
 #include "ui/gl/gl_bindings.h"
 #include "ui/gl/gl_implementation.h"
@@ -158,9 +159,17 @@ GrGLFunction<R GR_GL_FUNCTION_TYPE(Args...)> bind_with_flush_on_mac(
     // Conditional may be optimized out because droppable_call is set at compile
     // time.
     if (!droppable_call || !HasInitializedNullDrawGLBindings()) {
-      glFlush();
+      {
+        TRACE_EVENT0(
+            "gpu", "CreateGrGLInterface - bind_with_flush_on_mac - beforefunc")
+        glFlush();
+      }
       func(args...);
-      glFlush();
+      {
+        TRACE_EVENT0("gpu",
+                     "CreateGrGLInterface - bind_with_flush_on_mac - afterfunc")
+        glFlush();
+      }
     }
   };
 #else