Remove uses of external begin frame sources

content/renderer/gpu/render_widget_compositor_unittest.cc

Index: content/renderer/gpu/render_widget_compositor_unittest.cc
diff --git a/content/renderer/gpu/render_widget_compositor_unittest.cc b/content/renderer/gpu/render_widget_compositor_unittest.cc
index c6be82d430806e8c94433ce37154776cee3c0f69..d09dd86b0a085d308276bcd0629ba571da89aa52 100644
--- a/content/renderer/gpu/render_widget_compositor_unittest.cc
+++ b/content/renderer/gpu/render_widget_compositor_unittest.cc
@@ -45,10 +45,6 @@ class StubRenderWidgetCompositorDelegate
       bool fallback) override {
     return nullptr;
   }
-  std::unique_ptr<cc::BeginFrameSource> CreateExternalBeginFrameSource()
-      override {
-    return nullptr;
-  }
   void DidCommitAndDrawCompositorFrame() override {}
   void DidCommitCompositorFrame() override {}
   void DidCompletePageScaleAnimation() override {}
@@ -95,14 +91,6 @@ class FakeRenderWidgetCompositorDelegate
         std::move(context_provider));
   }
 
-  std::unique_ptr<cc::BeginFrameSource> CreateExternalBeginFrameSource()
-      override {
-    double refresh_rate = 200.0;
-    bool tick_automatically = true;
-    return base::MakeUnique<cc::FakeExternalBeginFrameSource>(
-        refresh_rate, tick_automatically);
-  }
-
   void add_success() {
     if (last_create_was_fallback_)
       ++num_fallback_successes_;