Fix viz_unittests to build with Vulkan enabled

viz_unittests currently do not build with Vulkan enabled.
One of the unit tests is GL related and can probably just have a
NOTREACHED().
The other unit test might benefit from a proper Vulkan code path. But
the immediate goal is to just get Vulkan enabled by default quickly. We
can later circle back and add a proper Vulkan code path to the overlay
test if it would be correct.

BUG=852531

Cq-Include-Trybots: luci.chromium.try:android_optional_gpu_tests_rel
Change-Id: I02a5bd1224575b452e92e3c147ab0c8d0efef76b
Reviewed-on: https://chromium-review.googlesource.com/1099755Reviewed-by: Antoine Labour <piman@chromium.org>
Commit-Queue: Chris Blume <cblume@chromium.org>
Cr-Commit-Position: refs/heads/master@{#567014}

components/viz/service/display/gl_renderer_unittest.cc

@@ -1933,6 +1933,12 @@ class MockOutputSurface : public OutputSurface {
   MOCK_METHOD0(GetFramebufferCopyTextureFormat, GLenum());
   MOCK_METHOD1(SwapBuffers_, void(OutputSurfaceFrame& frame));  // NOLINT
   void SwapBuffers(OutputSurfaceFrame frame) override { SwapBuffers_(frame); }
+#if BUILDFLAG(ENABLE_VULKAN)
+  gpu::VulkanSurface* GetVulkanSurface() override {
+    NOTREACHED();
+    return nullptr;
+  }
+#endif
   MOCK_CONST_METHOD0(GetOverlayCandidateValidator,
                      OverlayCandidateValidator*());
   MOCK_CONST_METHOD0(IsDisplayedAsOverlayPlane, bool());

components/viz/service/display/overlay_unittest.cc

@@ -204,6 +204,12 @@ class OverlayOutputSurface : public OutputSurface {
                bool has_alpha,
                bool use_stencil) override {}
   void SwapBuffers(OutputSurfaceFrame frame) override {}
+#if BUILDFLAG(ENABLE_VULKAN)
+  gpu::VulkanSurface* GetVulkanSurface() override {
+    NOTREACHED();
+    return nullptr;
+  }
+#endif
   uint32_t GetFramebufferCopyTextureFormat() override {
     // TestContextProvider has no real framebuffer, just use RGB.
     return GL_RGB;