Only call make gl context current if not already current

[iskakaushik]

Before: go/gl-context-before-fltt took ~2.6 seconds

After: go/gl-context-after-fltt took ~7 ms

[flutter-dashboard]

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[dnfield]

Change looks good but should have a test.

One way to test this woul dbe to delegate the eglMakeCurrent call and make sure it doesn't get called when eglGetCurrent returns the current one.

[dnfield]

I think at worst this should be freeing up CPU time where we are currently blocking on a buffer dequeue, but I'm curious how much raster time it actually gets us.

[jason-simmons]

Check eglGetCurrentSurface and eglGetCurrentDisplay in addition to the EGL context

[iskakaushik]

@dnfield I was looking into writing a test for this. This seems very close to the OpenGL + Android specific, there aren't any tests that test things in AndroidEGLSurface. If we were to write a test that ensures that we would not call MakeCurrent if context is current, we would want to essentially mock out IsContextCurrent altogether which seems to add very little value.

There aren't any tests for CreatePbufferSurface which will be the real test for this situation. I'm open to other ideas on what a good place to test would be.

[dnfield]

I think you can add a test in android_context_gl_unittests that does something like this:

GrMockOptions main_context_options;
  sk_sp<GrDirectContext> main_context =
      GrDirectContext::MakeMock(&main_context_options);
  auto environment = fml::MakeRefCounted<AndroidEnvironmentGL>();
  std::string thread_label =
      ::testing::UnitTest::GetInstance()->current_test_info()->name();

  ThreadHost thread_host(ThreadHost::ThreadHostConfig(
      thread_label,
      ThreadHost::Type::UI | ThreadHost::Type::RASTER | ThreadHost::Type::IO));
  TaskRunners task_runners = MakeTaskRunners(thread_label, thread_host);
  auto context = std::make_unique<AndroidContextGL>(
      AndroidRenderingAPI::kOpenGLES, environment, task_runners, 0);
  auto pbuffer = context->CreatePBufferSurface();
// etc.